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Chronoromancer

Version-matched official guide

Caterpillar Rearing - Complete System Guide

Activities & BusinessesSimplified Chinese availableV0.9.6.0
Guide noticeThis page contains gameplay and story spoilers and may describe mature systems.

The Caterpillar Rearing system is a long-term breeding ecosystem that spans the Medieval and Present eras. Players collect wild caterpillars from clickable spawns scattered across nearly every map, release them into the wild, and let populations grow through a real lifecycle simulation. Large populations unlock crystal rewards, special items, mystical breeding bonuses, silk for fabric crafting, and Marina's premium fishing bait.

This guide covers everything: how to find caterpillars, how the breeding lifecycle works, the research system, all 70 species, every spawn location with weighted probabilities, the reward thresholds, and integration with fishing and silk crafting.

Table of Contents

Quick Start

To start collecting caterpillars you need nothing — they appear as clickable wiggling sprites on maps automatically. To start breeding them, you need to visit either the Whispering Woods Uptown (Present) or the Whispering Woods (Medieval) and use the Manage Caterpillar Breeding action.

The first time you visit Whispering Woods Uptown (Present), Seraph auto-triggers a tutorial plot ("The Butterfly Effect") explaining the system.

The loop:

  1. Walk around any map — clickable caterpillar sprites spawn at certain hours.
  2. Click them to add to your collection.
  3. Visit either Whispering Woods location.
  4. Use the breeding action to open the Habitat screen.
  5. Press the "Add All" button to release every collected caterpillar to its appropriate era.
  6. Wait. Caterpillars mature, breed, and populate the ecosystem over in-game days.

Story Introduction

Plot file: seraph_caterpillar_tutorial.json — "The Butterfly Effect"

Trigger: Auto-fires the first time you enter present_forest_uptown (Whispering Woods Uptown). Blocked by the seraph_caterpillar_tutorial_completed flag after the first run. Awards +5 Seraph relationship.

Seraph greets you and explains that small actions can have large consequences across time. Raising butterflies and moths in the Present and Medieval eras helps restore the future — VOID's toxic influence on the Future-era forest can be reversed by sustaining large enough populations across the past and present.

Seraph covers:

  • Caterpillars produce silk for crafting and fish bait when populations get high
  • Use the Manage Caterpillar Breeding action at this location to oversee everything
  • Medieval populations provide mystical benefits to Present-era breeding
  • Researching caterpillar biology improves survival, breeding success, and lifespan

The plot ends with three response choices (polite / practical / enthusiastic) — flavor only, no mechanical difference.

Acquisition Methods

There are three distinct ways to get new caterpillars into your collection.

1. Clickable Discovery (primary method)

Caterpillars appear as wiggling clickable sprites on world maps. Each location defines its own species pool with weighted probabilities — a location only spawns species in its pool. Click the sprite to add the caterpillar to your collection. Triggers a respawn cooldown (2–10 days) before another caterpillar can appear at that location.

2. Hiking & Special Discovery actions

Two actions use the special_caterpillar_discovery action type:

  • Hike Mountains (Present-era, at Mountains Uptown)
  • Climb Mountain (Medieval-era, at Mountain Foothills)

These don't roll from a single location pool. Instead they pull from the union of every species in every pool of the player's current era, and pick one with equal probability.

This means every species that exists in any pool of the current era has the same chance of being found via hiking, including rare and epic species that would otherwise be very weighted-low at specific locations. Hiking is a fast way to round out a collection once you've discovered most pool locations.

The action displays a unique popup (show_hiking_caterpillar_discovery) with flavor text about hiking the trail and finding a caterpillar. No respawn cooldown like clickable spawns — you can keep performing the action as often as the action's energy/time/daily-limit constraints allow.

Key implication: species not in any pool of an era cannot be obtained via hiking either. The pool is the gate.

3. Tutorial Quest Rewards

The Tutorial Quest System (tutorial_quest_system.rpy) supports a caterpillars reward type that grants a specific species and amount directly to the player's collection on quest completion.

Confirmed quest using this:

  • tq_11_bug_collector ("Discover 10 unique species") — awards 5× Comet Moth (species 62)

This is the second acquisition path for species 62 in addition to the Evolution Tracking 50-point research milestone.

Research milestones (4th path)

Five "Special Research" species (61–65) are awarded via the Research System's Evolution Tracking milestones (25/50/75/100 points) and the Grand Master reward (all 5 paths at 100). Species 62 (Comet Moth) also has an alternate path via tq_11_bug_collector. The other four (61, 63, 64, 65) are research-only.

Discovery System (Clickable Spawns)

How spawns work:

  • Each location defines a species pool (a dict of species_id to weight).
  • When you enter the location, the system rolls one species using random.choices weighted by these numbers.
  • The selected species "sticks" until you click it or leave the location and return after respawn.
  • Caterpillars only render during their location's time window (some are 24-hour, some are daylight only).
  • After clicking, the location enters a respawn cooldown measured in days. Common locations respawn faster (2–3 days), epic/rare locations slower (5–10 days).
  • The clickable sprite is the same generic graphic for every species, just tinted with the location's location_tint color — so you can't tell what species is there until you click.

Clicking a caterpillar:

  1. Increments your collection count for that species.
  2. Sets the location's respawn timer (next available = current_day + respawn_days).
  3. Opens the Caterpillar Collection Popup showing species image, name, scientific name, rarity, size, growth time, era, description, and a "NEW DISCOVERY!" / "Found Again!" / "Ecosystem Species" banner.

Collection vs. Wild:

  • Caterpillars you click go into caterpillars_collected — your personal collection.
  • Releasing them moves them into the wild ecosystem (individual_caterpillars per era), where breeding happens.
  • Once released, they leave your collection. You can have a species in collection, in wild, or both.
  • The Habitat screen has an "Add All to Auto Era" button that drops every collected caterpillar into its native era.

Add All routing: Every species has a fixed era field in its data. When you press Add All, the system reads each collected species' actual era from the data and routes it there. Medieval-era species always go to Medieval, present-era species always go to Present.

No partial release UI: The underlying release_caterpillar_to_wild(species_id, era, count) function supports per-species and partial-count releases, but the Habitat screen only exposes the Add All button. There's no UI to release a single species, hold some back, or split a species across eras. Add All is all-or-nothing.

Total species: 70 (Moths 1–30, Butterflies 31–60, Special 61–65, Water 66–70).

Habitat Management Screen

Access this by using the Manage Caterpillar Breeding action at Whispering Woods (Medieval) or Whispering Woods Uptown (Present). Both are time_cost=0, money_cost=0, no relationship gates — always available, always free.

Top banner: shows three population summaries — Present Era total, Medieval Era total, and Combined Ecosystem total.

Three action buttons (top right):

  • Add All (paw icon) — releases every collected caterpillar to its native era
  • Caterpillar Info — opens the detailed population breakdown screen
  • Research — opens the Research Laboratory screen

Live ecosystem display: caterpillars and adults that exist in the wild render as wiggling sprites scattered across the screen. Present-era species appear on the left half, medieval-era on the right half. Caterpillars in the lower half, adults in the upper half. Sprite size scales with the species size field (small=0.7×, medium=1.0×, large=1.4×). Position is deterministic per species — same species always appears in the same spot until populations change.

Close button at bottom center restores the persistent UI when exiting.

Detailed Population Screen

Opened via the Caterpillar Info button. Modal screen showing the full per-species breakdown for the combined ecosystem.

Header stats:

  • Total Population — combined medieval + present
  • Species Count — how many distinct species are alive
  • Birds Fed — running caterpillar_deaths_total (failed survival rolls during maturation)
  • Wallflowers — running adult_wallflowers_total (failed mating rolls)

Per-species rows show: species name, era (Present/Medieval), total population, adult count labeled by category (Moths / Butterflies / Special Moths / Aquatic Moths / Aquatic Butterflies), plus two clickable icons for caterpillar popup and adult popup.

The "Aquatic Moths" label is used for water species 68 and 70 (both have moth-style adults). 66, 67, 69 use the "Aquatic Butterflies" label.

Backup System (right side panel): shows a backup snapshot with a "Restore Backup" button. When the system is active, displays Backup Total, Backup Species count, and Total Research points. When inactive, fields show "TBA" and the restore button is greyed out. The backup system is a safety net for save corruption, not a player-facing save tool.

Important — 50/50 fake split for abstracted populations: when a species has been moved to abstracted tracking (1,000+ population), the system no longer tracks individuals. The population breakdown screen displays abstracted species as a fake 50/50 split between caterpillars and adults purely for display. The real backend stores a single total count.

Breeding Lifecycle

The core simulation is in caterpillar_habitats.rpy and runs once per in-game day via daily_caterpillar_update(), called from advance_time() whenever the day rolls over.

Base configuration (BASE_BREEDING_CONFIG):

  • Caterpillar survival rate (to adulthood): 70%
  • Adult lifespan: 7 days
  • Breeding delay (days as adult before mating): 4 days
  • Mating success rate: 50%
  • Babies per successful mating: 50–100 (random per breeder)
  • Baby survival rate (to caterpillar stage): 10%

Concrete timeline example (no research, no medieval bonuses)

A Cecropia Moth (growth_time = 8) released as a caterpillar on Day 10:

  • Day 10: Released as Gen 1 caterpillar
  • Day 18: Reaches age 8, rolls survival vs 70% → if survives, becomes Gen 1 adult on Day 18
  • Day 22: Adult age = 4, equals breeding_delay → eligible to breed (Gen 1, so 100% eligible). Rolls vs 50% mating success. If successful, produces 50–100 babies × 10% survival ≈ 5–10 Gen 2 caterpillars same day
  • Day 25: Adult age = 7, exceeds adult_lifespan → removed from ecosystem
  • Day 25 onward: Gen 2 caterpillars continue maturing, eventually breed (only 50% eligible since Gen 2+)

Total turnaround: 1 caterpillar released → 5–10 new caterpillars in 12 days.

The four daily steps (per era)

  1. Caterpillar Maturation: Each caterpillar group ages by 1 day. When age ≥ species growth_time (5–15 days depending on species), each caterpillar rolls survival vs. modified survival rate (base × era_bonus). Survivors become adults the same day. Deaths increment caterpillar_deaths_total.

  2. Adult Breeding: When an adult group's age equals exactly breeding_delay (Day 4 of adulthood):

    • Generation 1 adults: ALL of them are eligible breeders (full count)
    • Generation 2+ adults: Only 50% are eligible breeders (representing females; int(count * 0.5))
    • Each potential breeder rolls vs. modified mating success
    • Failed breeders increment adult_wallflowers_total
    • Each successful breeder produces a random baby_min–baby_max babies (rolled per breeder)
    • At 100K+ medieval pop in Present era, each successful breeder also rolls a 10% chance to produce a SECOND batch of babies (the Double Breeding bonus)
    • All babies roll vs. baby survival rate
    • Surviving babies become Gen+1 caterpillars the same day

    Important: breeding only happens on the EXACT day adults turn 4. Adults don't breed multiple times across their lifespan — but the Double Breeding 10% chance means a single adult can produce two batches on its breeding day.

  3. Adult Cleanup: When an adult group's age exceeds the modified adult lifespan (int(base × era_bonus)), it's removed entirely. With 100K+ medieval bonus, lifespan goes to 7 × 2.0 = 14 days.

  4. Abstracted Population Growth: For species moved to abstracted tracking (1,000+ in an era):

    • No per-individual rolls
    • Growth rate calculated as: 1.0 + (0.5 × mating × avg_babies × baby_survival / 1000)
    • Population multiplied by growth rate each day

Probabilistic vs. Deterministic Survival

The function apply_probabilistic_survival(count, rate, threshold=1000):

  • Groups of ≤1000: each individual rolls separately (true random)
  • Groups >1000: flat multiplier round(count × rate) (deterministic)

Population totals

After every daily update, update_era_population_totals() recalculates medieval_population_total and present_population_total by summing all caterpillars + adults + abstracted populations in each era. These totals drive all the reward thresholds.

Generational scaling

Because Gen 1 adults all breed (100%) and Gen 2+ adults only breed at 50%, the first generation produces a huge growth burst that scales down in later generations. Releasing fresh caterpillars from your collection gives you "free" Gen 1 adults that breed at full rate.

Research System

Open from the Habitat screen via the Research button. The research screen has 5 paths, each capped at 100 points.

Cost per research session:

  • 2 hours of in-game time
  • 30 energy
  • 30 calm

Points gained per session:

  • Base: 5 points
  • Intelligence bonus: +1 per 8 Intelligence (using get_stat_with_modifiers)
  • Researching skill bonus: ×2 multiplier if the player has the "Researching" skill
  • Cap: total points per session capped at 20 With high Intelligence (~64+) and the Researching skill, you can hit the 20-point cap per session. Without those, you might gain 5–10 per session.

The 5 research paths

  • Species Research: +10% caterpillar survival at 100 points (70% → 80%). Formula: survival += points/1000
  • Breeding Research: +10% mating success at 100 points (50% → 60%). Formula: mating += points/1000
  • Population Analysis: +100 max babies per mating at 100 points (100 → 200). Formula: baby_max += points
  • Evolution Tracking: +10 days adult lifespan at 100 points (7 → 17). Formula: lifespan += points/10
  • Environmental Research: +20% baby survival at 100 points (10% → 30%). Formula: baby_survival += (points × 2)/1000

Evolution Tracking species rewards

Reaching milestones in the Evolution path unlocks special species directly into your collection (5 specimens each):

  • 25 points: Species 61 — Madagascar Sunset Moth
  • 50 points: Species 62 — Comet Moth (also available via tq_11_bug_collector tutorial quest)
  • 75 points: Species 63 — Vampire Moth
  • 100 points: Species 64 — White Witch Moth

The 20-points-per-session cap exists specifically to prevent skipping these milestones in one sitting.

Grand Master reward

When all 5 paths reach 100, you unlock species 65 — Chronos Moth (legendary, time-themed) with 5 specimens added to your collection.

Research display

The Research Laboratory screen shows a live scientific data readout including: current breeding efficiency multiplier, larval/mating/baby survival rates, maximum offspring and adult longevity, cross-era synergy (medieval bonus tier), both era population totals, maximum generation reached, research efficiency per session, intelligence bonus, biodiversity index, ecological balance (total caterpillar deaths), and population milestone progress.

Medieval Mystical Bonuses

Strong Medieval populations provide passive bonuses to Present-era breeding (they do NOT bonus Medieval breeding itself). The bonus tier is determined solely by medieval_population_total.

  • 0 – 999 medieval pop: no bonus (×1.0 across all stats)
  • 1,000 – 9,999: ×1.1 cat. survival, ×1.1 adult lifespan, ×1.1 mating success
  • 10,000 – 49,999: ×1.1 cat. survival, ×1.2 adult lifespan, ×1.1 mating success
  • 50,000 – 99,999: ×1.2 cat. survival, ×1.5 adult lifespan, ×1.3 mating success
  • 100,000+: ×1.33 cat. survival, ×2.0 adult lifespan, ×1.6 mating success, plus 10% Double Breeding chance per successful breeder

These multipliers are applied on top of base values + research bonuses (multiplicatively). Survival and mating are clamped at 1.0 max — you can't exceed 100%.

The Double Breeding bonus at 100K+ rolls per successful breeder during the breeding step. On a successful 10% roll, that breeder produces a second batch of 50–100 babies in addition to their first batch (both batches go through baby_survival_rate together).

Population Rewards

These are auto-triggering plot rewards that fire when you visit the right location with medieval_population_total + present_population_total at or above the threshold.

  • 500,000 total: +1 Crystal, +5 Seraph, +5 Lillian. Either Whispering Woods. Plot: Ecosystem Stabilization.
  • 5,000,000 total: +3 Crystals, +5 Seraph, +5 Lillian. Either Whispering Woods. Plot: Forest Transformation.
  • 10,000,000 total: Silken Moth Cloth (maid item). Whispering Woods (Medieval) only. Plot: The Moth Lady's Blessing.
  • 15,000,000 total: Silk Uniform (worker item). Whispering Woods (Medieval) only. Plot: The Moth Lady's Gift.
  • 100,000,000 total: +5 Crystals, +5 Seraph, +5 Lillian. Either Whispering Woods. Plot: Secret Guardian.

Each plot has a one-shot completion handler that flips a flag (e.g. caterpillar_reward_500000_claimed) so it cannot fire twice.

Note on Doomsday Timer: Caterpillar populations do NOT affect the Doomsday Timer in any way. The Doomsday Timer is only extended through specific story achievements and the "Extend Doomsday" crystal purchase (+10 days).

Practical Uses

Silk Collection

The "Collect Moth Silk" resource action (collect_moth_silk_function) uses your combined population to determine fabric tier rewards:

  • 1 – 99 total: 1–2 common, 0 rare, 0 epic
  • 100 – 999: 1–3 common, 0 rare, 0 epic
  • 1,000 – 9,999: 2–4 common, 70% chance for 1–2 rare, 0 epic
  • 10,000 – 99,999: 4–7 common, 1–3 rare, 30% chance for 1 epic
  • 100,000 – 999,999: 6–10 common, 2–5 rare, 60% chance for 1–2 epic
  • 1,000,000 – 9,999,999: 12–18 common, 4–8 rare, 1–3 epic
  • 10,000,000+: 20–30 common, 8–12 rare, 3–5 epic

Perception bonus: A separate roll vs. the player's modified Perception stat grants 1 bonus fabric on success — a Rare by default, an Epic if the Luck roll also succeeds.

There is also a 1% chance per resource-collection action to gain +1 Luck.

Fish Bait — Marina's Caterpillar Bait

Plot file: marina_caterpillar_bait.json. Action: "Caterpillar Bait" at medieval_fishing_hut_interior.

Unlock requirements (all must be true):

  • Marina at minimum acknowledged relationship stage
  • Combined ecosystem population at or above 1,000,000
  • marina_caterpillar_bait_unlocked flag NOT yet set
  • At Marina's fishing hut, daylight hours

The action is time_cost=0, money_cost=0 — costs nothing besides population and relationship. Once triggered, you bring Marina a sack of caterpillars in a quick plot scene with three response choices (kind +4 / funny +5 / adult +3 Marina relationship). Total relationship gain: 17 base + choice bonus.

Effect (permanent passive once unlocked):

The fishing minigame (minigame_fishing.rpy) auto-detects the marina_caterpillar_bait_unlocked flag and applies these buffs to every fishing run:

  • Bait Supply: Unlimited — replaces the consumable bait system entirely
  • Ring spawn rate: -4 frames (faster ring spawning, base 20 frames per ring). Stacks with Master Baiter (-4) and Sashimi's Kiss (-3)
  • Ring rarity shift: common -12%, rare +4%, epic +8% (additive)

There is no "select bait" UI — the bonuses apply automatically once unlocked.

Species Database

70 total species across 4 categories. Each entry has: name, scientific_name, adult_name, descriptions, rarity (common / rare / epic / legendary), era (present / medieval), color_tint, size (small / medium / large), and growth_time in days.

Moths (Species 1–30) — caterpillar_data_moths.rpy

ID  Name                       Rarity     Era       Size    Growth
1   Silkworm                   common     present   medium  5
2   Cecropia Moth              rare       present   large   8
3   Luna Moth                  rare       present   large   7
4   Polyphemus Moth            rare       present   large   7
5   Atlas Moth                 epic       present   large   9
6   Imperial Moth              rare       present   large   8
7   Io Moth                    common     present   medium  6
8   Vine Hawkmoth              common     present   large   6
9   Tobacco Hornworm           common     present   large   6
10  Tomato Hornworm            common     present   large   6
11  White-marked Tussock       common     present   medium  5
12  Woolly Bear                common     present   medium  5
13  Gypsy Moth                 common     present   medium  7
14  Promethea Moth             rare       present   large   7
15  Buck Moth                  rare       present   medium  6
16  Elephant Hawkmoth          rare       medieval  large   7
17  Privet Hawkmoth            rare       medieval  large   8
18  Death's-head Hawkmoth      epic       medieval  large   9
19  Puss Moth                  rare       medieval  large   8
20  Lime Hawkmoth              common     medieval  large   7
21  Eyed Hawkmoth              common     medieval  large   7
22  Poplar Hawkmoth            common     medieval  large   6
23  Cinnabar Moth              common     medieval  medium  5
24  Garden Tiger Moth          common     medieval  medium  6
25  White Ermine Moth          common     medieval  medium  5
26  Emperor Moth               rare       medieval  medium  7
27  Burnished Brass Moth       common     medieval  small   5
28  Hummingbird Clearwing      rare       present   medium  6
29  Rosy Maple Moth            rare       present   medium  6
30  Giant Leopard Moth         common     present   medium  7

Butterflies (Species 31–60) — caterpillar_data_butterflies.rpy

ID  Name                         Rarity      Era       Size    Growth
31  Black Swallowtail            common      present   large   6
32  Eastern Tiger Swallowtail    common      present   large   7
33  Giant Swallowtail            common      present   large   8
34  Spicebush Swallowtail        common      present   large   6
35  Pipevine Swallowtail         rare        present   medium  7
36  Zebra Swallowtail            rare        present   medium  6
37  Red Admiral                  common      present   medium  5
38  Painted Lady                 common      present   medium  5
39  American Lady                common      present   medium  5
40  Mourning Cloak               rare        present   large   6
41  Question Mark                common      present   medium  5
42  Comma                        common      medieval  medium  6
43  Great Spangled Fritillary    rare        present   medium  8
44  Gulf Fritillary              common      present   medium  6
45  Zebra Longwing               rare        present   medium  7
46  Cloudless Sulphur            common      present   large   6
47  Orange Sulphur               common      present   medium  5
48  Clouded Yellow               common      medieval  medium  5
49  Brimstone                    common      medieval  medium  6
50  Orange-tip                   common      medieval  small   5
51  Large White                  common      medieval  medium  5
52  Cabbage White                common      present   small   4
53  Green-veined White           common      medieval  small   5
54  Peacock                      common      medieval  medium  6
55  Small Tortoiseshell          common      medieval  medium  5
56  Monarch                      common      present   medium  6
57  Palos Verdes Blue            legendary   present   small   9
58  Karner Blue                  legendary   present   small   9
59  Mitchell's Satyr             legendary   present   small   10
60  Schaus' Swallowtail          legendary   present   large   10

Special Research Species (61–65) — caterpillar_data_special.rpy

All five are Legendary. Awarded via Evolution research milestones (25/50/75/100) and Grand Master (all paths at 100). Species 62 (Comet Moth) also has an alternate path via the tq_11_bug_collector tutorial quest.

ID  Name                       Era       Size    Growth  Unlock
61  Madagascar Sunset Moth     present   large   12      Evolution 25
62  Comet Moth                 medieval  large   15      Evolution 50 (or tq_11_bug_collector)
63  Vampire Moth               present   medium  11      Evolution 75
64  White Witch Moth           medieval  large   14      Evolution 100
65  Chronos Moth               present   medium  10      All 5 paths at 100

Water Species (66–70) — caterpillar_data_water.rpy

Found exclusively at Waterfall Uptown.

ID  Name                     Rarity      Era      Size   Growth
66  Bog Copper               common      present  small  5
67  Baltimore Checkerspot    common      present  medium 6
68  Brown China-mark         rare        present  small  8
69  Swamp Metalmark          epic        present  small  10
70  Water Veneer             legendary   present  small  12

Spawn Locations

Caterpillar locations are defined in caterpillar_locations.rpy. There are 39 total spawn maps — 19 in the Present era and 20 in the Medieval era (including Brothel Garden, which is era="Medieval"). Each defines its species pool with weighted probabilities, time window, respawn delay (days), and tint color.

How weights work

Each pool is a dict of species_id to weight. When you enter a location, the system rolls one species using random.choices weighted by these numbers. Most pools sum to 100, but the system supports any totals.

Present-era locations (19)

Location                             Time     Respawn  Species Pool (weight)
Housing Block                        24h      3d       Cabbage White 40, Vine Hawkmoth 25, Red Admiral 20, American Lady 10, Gypsy 5
Shopping Mall Exterior               9-19     4d       Cabbage White 25, Red Admiral 25, E. Tiger Swallowtail 20, Black Swallowtail 15, Atlas 15
Back Alley Downtown                  24h      4d       American Lady 25, Painted Lady 25, Mourning Cloak 20, Great Spangled Fritillary 15, Death's-head 15
Cafe Exterior                        24h      2d       Painted Lady 35, Red Admiral 25, Cabbage White 20, Orange Sulphur 15, Io 5
Park Uptown                          24h      3d       Red Admiral 25, Painted Lady 20, Monarch 20, Gulf Fritillary 15, Great Spangled 10, Mourning Cloak 5, Zebra Longwing 5
Beach Uptown                         24h      4d       Gulf Fritillary 40, Cloudless Sulphur 30, Orange Sulphur 20, Zebra Longwing 7, Zebra Swallowtail 3
Forest Uptown                        24h      6d       Cecropia 25, Luna 20, Polyphemus 20, Imperial 15, Promethea 10, Atlas 5, Rosy Maple 5
Townhall Uptown                      7-16     6d       Cecropia 25, Luna 20, Polyphemus 20, Io 15, Tobacco Hornworm 10, Atlas 5, Rosy Maple 5
Mountains Uptown                     24h      4d       Luna 30, Mourning Cloak 25, Buck 20, Woolly Bear 15, Giant Leopard 7, Gypsy 3
University Campus                    7-24     6d       Painted Lady 35, Red Admiral 30, Cabbage White 20, Orange Sulphur 10, Io 5
Apartment Complex Downtown           24h      3d       American Lady 40, Cabbage White 25, Painted Lady 20, White-marked Tussock 10, Gypsy 5
Park Downtown                        24h      5d       Great Spangled Fritillary 35, Red Admiral 25, Gulf Fritillary 20, Painted Lady 15, Monarch 5
Spa Downtown                         24h      4d       Black Swallowtail 40, E. Tiger Swallowtail 35, Cabbage White 15, Hummingbird Clearwing 7, Giant Swallowtail 3
City Street Downtown                 24h      4d       E. Tiger Swallowtail 35, Black Swallowtail 30, Cabbage White 20, American Lady 10, Gypsy 5
Waterfall Uptown                     24h      2d       Bog Copper 35, Baltimore Checkerspot 30, Brown China-mark 18, Swamp Metalmark 12, Water Veneer 5
Butterfly Pavilion                   24h      4d       Silkworm 25, Spicebush Swallowtail 20, Pipevine Swallowtail 15, Karner Blue 12, Schaus' Swallowtail 10, Palos Verdes Blue 8, Mitchell's Satyr 6, Tomato Hornworm 4
Boardwalk                            24h      5d       Question Mark 35, Schaus' Swallowtail 25, Palos Verdes Blue 20, Mitchell's Satyr 20
Patron Statue                        24h      4d       Question Mark 30, Spicebush Swallowtail 25, Silkworm 20, Tomato Hornworm 15, Pipevine Swallowtail 10
Mansion Exterior (Downtown)          18-22    4d       Karner Blue 35, Tomato Hornworm 35, Silkworm 30

Medieval-era locations (20)

Location                             Time     Respawn  Species Pool (weight)
Ancient Earth Shrine                 24h      5d       Death's-head 30, Elephant Hawkmoth 20, Privet Hawkmoth 20, Emperor 15, Puss 10, Atlas 5
Fishing Hut Interior                 24h      3d       Garden Tiger 40, White Ermine 30, Large White 20, Cabbage White 7, Burnished Brass 3
Mystic's Meditation Grove            24h      5d       Emperor 30, Puss 20, Luna 15, Polyphemus 15, Death's-head 15, Atlas 5
Royal Hunting Grounds Edge           7-19     4d       Privet Hawkmoth 35, Elephant Hawkmoth 25, Cecropia 15, Polyphemus 10, Death's-head 10, Imperial 5
Knights Training Grounds             6-18     3d       White Ermine 40, Garden Tiger 30, Comma 15, Large White 10, Cinnabar 5
Peasant Huts                         24h      3d       Large White 45, Cabbage White 35, Green-veined White 15, Orange-tip 5
Monastery Scriptoria                 24h      4d       Peacock 40, Small Tortoiseshell 30, Comma 15, Green-veined White 10, Burnished Brass 5
Caravan Rest Stop                    24h      3d       Comma 40, Clouded Yellow 30, Brimstone 20, Orange-tip 7, Garden Tiger 3
Village Healer's Hut                 24h      3d       Orange-tip 40, Brimstone 30, Clouded Yellow 20, Green-veined White 7, Cinnabar 3
Bandit Hideout                       24h      7d       Death's-head 50, Puss 25, Elephant Hawkmoth 15, Emperor 5, Atlas 5
Grand Bazaar Demesne                 24h      3d       Clouded Yellow 35, Brimstone 30, Comma 20, Peacock 10, Burnished Brass 5
Hot Springs Demesne                  24h      3d       Brimstone 40, Clouded Yellow 30, Orange-tip 20, Small Tortoiseshell 7, Eyed Hawkmoth 3
Secluded Sanctuary                   24h      5d       Puss 30, Emperor 25, Luna 20, Polyphemus 15, White Ermine 7, Atlas 3
Rural Farm                           24h      2d       Cabbage White 45, Large White 35, Green-veined White 15, Orange-tip 3, Cinnabar 2
Archery Range                        24h      3d       Small Tortoiseshell 40, Peacock 30, Comma 20, White Ermine 7, Eyed Hawkmoth 3
Castle Garden                        24h      3d       Green-veined White 35, Peacock 30, Small Tortoiseshell 20, Orange-tip 10, Emperor 5
Whispering Woods                     24h      5d       Polyphemus 30, Luna 25, Cecropia 20, Puss 15, Emperor 7, Atlas 3
Witch's Hut                          24h      10d      Death's-head 20, Atlas 15, Luna 15, Emperor 12, Puss 10, Cecropia 10, Polyphemus 8, Elephant Hawkmoth 5, Privet Hawkmoth 3, Imperial 2
Forest Clearing                      24h      2d       Large White 25, Cabbage White 20, Garden Tiger 15, White Ermine 15, Comma 10, Peacock 5, Small Tortoiseshell 5, Orange-tip 3, Brimstone 2
Brothel Garden                       24h      3d       Lime Hawkmoth 50, Poplar Hawkmoth 50  (player-owned, requires brothel ownership)

Time-window locations (matter for travel planning)

Most locations are 24-hour, but a few only spawn during specific in-game hours:

  • Shopping Mall Exterior: 9 AM – 7 PM (skip if traveling at night)
  • Townhall Uptown: 7 AM – 4 PM (tightest window — afternoon required)
  • University Campus: 7 AM – midnight (early-morning window only blocked)
  • Royal Hunting Grounds Edge: 7 AM – 7 PM (daylight only)
  • Knights Training Grounds: 6 AM – 6 PM (daylight only)
  • Mansion Exterior (Downtown): 6 PM – 10 PM (evening only)

If you visit these at the wrong hour, no caterpillar will appear regardless of the respawn timer.

Where To Farm What

Reverse-lookup table — given a species you want, the locations that spawn it ranked by weight.

Epic-tier species

Atlas Moth (5) — present-era epic, appears in BOTH eras' pools:

  • Shopping Mall Exterior (Present): 15
  • Witch's Hut (Medieval): 15
  • Forest Uptown (Present): 5
  • Townhall Uptown (Present): 5
  • Ancient Earth Shrine (Medieval): 5
  • Bandit Hideout (Medieval): 5
  • Mystic's Meditation Grove (Medieval): 5
  • Whispering Woods (Medieval): 3
  • Secluded Sanctuary (Medieval): 3

Death's-head Hawkmoth (18) — medieval-era epic, appears in present-era pools too:

  • Bandit Hideout (Medieval): 50
  • Ancient Earth Shrine (Medieval): 30
  • Witch's Hut (Medieval): 20
  • Back Alley Downtown (Present): 15
  • Mystic's Meditation Grove (Medieval): 15
  • Royal Hunting Grounds Edge (Medieval): 10

Swamp Metalmark (69) — water epic:

  • Waterfall Uptown (Present): 12

Legendary-tier wild species

  • Water Veneer (70): Waterfall Uptown only, weight 5
  • Palos Verdes Blue (57): Boardwalk 20, Butterfly Pavilion 8
  • Karner Blue (58): Mansion Exterior (Downtown) 35, Butterfly Pavilion 12
  • Mitchell's Satyr (59): Boardwalk 20, Butterfly Pavilion 6
  • Schaus' Swallowtail (60): Boardwalk 25, Butterfly Pavilion 10

Rare species — best locations

  • Cecropia Moth (2): Forest Uptown 25, Townhall Uptown 25, Whispering Woods 20, Royal Hunting Grounds 15, Witch's Hut 10
  • Luna Moth (3): Mountains Uptown 30, Whispering Woods 25, Secluded Sanctuary 20, Forest Uptown 20, Townhall Uptown 20, Witch's Hut 15, Mystic's Grove 15
  • Polyphemus Moth (4): Whispering Woods 30, Forest Uptown 20, Townhall Uptown 20, Mystic's Grove 15, Secluded Sanctuary 15, Royal Hunting Grounds 10, Witch's Hut 8
  • Imperial Moth (6): Forest Uptown 15, Royal Hunting Grounds 5, Witch's Hut 2
  • Promethea Moth (14): Forest Uptown only, weight 10
  • Buck Moth (15): Mountains Uptown only, weight 20
  • Elephant Hawkmoth (16): Royal Hunting Grounds 25, Ancient Earth Shrine 20, Bandit Hideout 15, Witch's Hut 5
  • Privet Hawkmoth (17): Royal Hunting Grounds 35, Ancient Earth Shrine 20, Witch's Hut 3
  • Puss Moth (19): Secluded Sanctuary 30, Bandit Hideout 25, Mystic's Grove 20, Whispering Woods 15, Witch's Hut 10, Ancient Earth Shrine 10
  • Emperor Moth (26): Mystic's Grove 30, Secluded Sanctuary 25, Ancient Earth Shrine 15, Witch's Hut 12, Whispering Woods 7, Castle Garden 5, Bandit Hideout 5
  • Hummingbird Clearwing (28): Spa Downtown only, weight 7
  • Rosy Maple Moth (29): Forest Uptown 5, Townhall Uptown 5
  • Pipevine Swallowtail (35): Butterfly Pavilion 15, Patron Statue 10
  • Zebra Swallowtail (36): Beach Uptown only, weight 3
  • Mourning Cloak (40): Mountains Uptown 25, Back Alley Downtown 20, Park Uptown 5
  • Great Spangled Fritillary (43): Park Downtown 35, Back Alley Downtown 15, Park Uptown 10
  • Zebra Longwing (45): Beach Uptown 7, Park Uptown 5

Newly-added species (5 newest locations)

  • Silkworm (1): Mansion Exterior (Downtown) 30, Patron Statue 20, Butterfly Pavilion 25
  • Tomato Hornworm (10): Mansion Exterior (Downtown) 35, Patron Statue 15, Butterfly Pavilion 4
  • Lime Hawkmoth (20): Brothel Garden 50 (only location)
  • Poplar Hawkmoth (22): Brothel Garden 50 (only location)
  • Spicebush Swallowtail (34): Patron Statue 25, Butterfly Pavilion 20
  • Pipevine Swallowtail (35): Butterfly Pavilion 15, Patron Statue 10
  • Question Mark (41): Boardwalk 35, Patron Statue 30

Best epic-hunting routes

  • For Atlas: hit Witch's Hut (15%) and Shopping Mall Exterior (15%) on cooldown. Both have long respawns (10d, 4d) but the highest weights.
  • For Death's-head: Bandit Hideout (50%!) is by far the best, then Ancient Earth Shrine (30%). Both are medieval. Bandit Hideout's 7-day respawn is the trade-off.
  • For Legendary butterflies: Boardwalk (5d respawn) is the best one-stop for 3 of the 4 legendaries (Schaus' 25, Mitchell's Satyr 20, Palos Verdes 20). Butterfly Pavilion (4d respawn) has all 4 plus rare Pipevine but at lower weights. Mansion Exterior at evening hours is the dedicated Karner Blue location (35%).
  • For Lime/Poplar Hawkmoths: Brothel Garden is the only spawn location — exclusive to brothel-owning players. Each species has a 50% chance per spawn.

Save / Load

The caterpillar system has its own save/load module (caterpillar_save_load.rpy) plus a separate backup safety net (backup_save_load.rpy).

What's saved (3 categories)

Breeding state:

  • individual_caterpillars (per era, per birth_day, list of (gen, species_id, count) tuples)
  • individual_adults (same structure)
  • medieval_population_total, present_population_total
  • caterpillar_deaths_total, adult_wallflowers_total
  • population_rewards_unlocked list
  • abstracted_populations (per era, per species_id, total count)
  • habitat_data dict

Discovery state:

  • caterpillars_collected (per species_id: count, first_found, last_collected)
  • caterpillar_respawn_times (per location_key: respawn day)
  • current_location_selected_species (per location_key: species currently rolled)

Research state:

  • research_progress (5 paths, 0–100 each)
  • evolution_milestones_awarded list

Save version: 1.0

The save schema is tagged with 'version': '1.0' for future migration.

Anti-corruption protections in restore

The restore code includes several patches against past save corruption:

  • All species IDs are force-cast to int (old saves had string IDs)
  • All birth_day / adult_day keys are force-cast to int
  • Tuples are reconstructed as new tuples to break Ren'Py rollback contamination
  • If groups is somehow a dict (old contaminated save), it is converted to list via .values()
  • evolution_milestones_awarded is force-converted to list if it was stored as a dict

Auto-salvage of bloated saves

salvage_old_save_on_load(breeding_data): if a save is missing abstracted_populations, the system walks all detailed populations and abstracts any species at 1,000+ count. This converts pre-abstraction-system saves to the new memory-saving format on load.

Daily Backup System

A separate safety net handled by backup_save_load.rpy and triggered every day in advance_time (after daily_caterpillar_update).

Activation conditions (both required for first activation):

  • Combined population > 1,000
  • At least one research path > 0

Once activated, the backup stays active for the rest of the save.

Daily validation rules — restore from backup if either is true:

  • Population dropped 500+ since last backup
  • Any research path decreased since last backup

If neither corruption signal trips, the system updates the backup snapshot to current state. Otherwise, it silently restores from the previous backup, undoing whatever broke.

Manual restore button: The Detailed Population Screen exposes a "Restore Backup" button that calls manual_restore_backup(), force-restoring from whatever the current backup snapshot holds.

The backup tracks: population totals, research progress, full breeding/adult/abstracted data, discovery collection and respawn times, habitat data, deaths, wallflowers, evolution milestones, and rewards unlocked.

Day 1 Progression Path

A guided early-game route to your first 1M caterpillars. Assumes a fresh game with default stats.

Day 1–3: Discovery sweep

Goal: stock your collection with as many distinct species as possible.

  • Walk every present-era map. Click every wiggling caterpillar.
  • Visit Whispering Woods Uptown (Present) to trigger Seraph's tutorial.
  • Hit the medieval-era starter maps: Peasant Huts, Rural Farm, Caravan Rest Stop, Forest Clearing — these have short respawn timers (2–3 days) and high common-rate weights.
  • Don't worry about epic locations yet; their long respawns aren't worth optimizing this early.

You should have 8–15 species in collection by end of Day 3.

Day 3–10: First release & medieval foundation

Goal: get medieval populations to 1K for the first mystical bonus tier (×1.1 across all stats).

  • Visit Whispering Woods Uptown or Whispering Woods (Medieval), hit Add All. Your initial population kicks off breeding immediately.
  • Your medieval species (Comma, Garden Tiger, Whites, etc.) will breed in their era; presents (Red Admiral, Painted Lady, etc.) in theirs.
  • Continue daily map sweeps for fresh Gen 1 caterpillars — each new release adds a fresh 100% breeding cohort.
  • Population growth: ~5–10× per generation cycle (~12 days per cycle without research).

Day 10–30: Research kickoff

Goal: unlock Population Analysis 100 and Environmental Research 50+.

  • Once you have a population producing surplus, start spending sessions at the Research Lab.
  • Cost per session: 2hrs / 30 energy / 30 calm. Plan around your daily energy regen.
  • Priority: Population Analysis (doubles babies cap) → Environmental Research (triples baby survival).
  • Pick up the Researching skill if available — it doubles your research point gain.

Day 30–60: Hit the 500K reward

Goal: trigger the Ecosystem Stabilization plot.

  • Combined population should pass 500K naturally with research active and a sustained breeding loop.
  • Visit either Whispering Woods — the plot auto-triggers and awards +1 Crystal.
  • Continue research; aim for Evolution Tracking 25 to unlock species 61.

Day 60+: Compounding to 5M and beyond

Goal: push medieval to 100K for the strongest mystical bonus tier (which now includes the 10% Double Breeding bonus on top of all other multipliers), hit 5M combined, then 1M for Marina.

  • Once medieval pop crosses 100K, present-era breeding gets ×1.33 survival, ×2.0 lifespan, ×1.6 mating, plus 10% chance per breeder for a second batch of babies.
  • Combined growth becomes exponential. The 1M Marina threshold and 5M crystal reward usually fall close together.
  • Talk to Marina at the Medieval Fishing Hut at acknowledged+ relationship to deliver the caterpillar bait — permanent fishing minigame upgrade.
  • 10M and 15M unlock the Silken Moth Cloth and Silk Uniform via the Whispering Woods (Medieval) location specifically.

Tips & Strategy

Starting out

  • Click every caterpillar you see — they're free and the cooldowns mean you only see one per location every few days.
  • Hit Whispering Woods Uptown early to trigger Seraph's tutorial.
  • Press Add All on the Habitat screen to auto-route everything to its native era.
  • Don't stress about epic species early — Witch's Hut has a 10-day respawn, you'll get plenty over the course of a long game.

Population growth

  • Population grows exponentially once you hit a sustained breeding loop. Gen 1 adults all breed (not just half), so the first generation matters most — keep adding fresh caterpillars from the wild.
  • Each successful breeding produces 50–100 babies × 10% baby survival = ~5–10 new caterpillars per breeding pair, before research and medieval bonuses.
  • Build Medieval populations to 100K for the strongest mystical bonuses — at that tier you get ×1.33 survival, ×2.0 lifespan, ×1.6 mating, plus 10% Double Breeding chance per successful breeder. This compounds into massive Present-era growth.

Research priorities

  • Population Analysis is the highest-impact early path — doubling baby_max directly doubles your growth rate.
  • Environmental Research is the second most powerful — tripling baby survival from 10% to 30%.
  • Evolution Tracking is worth investing in for the four free legendary species rewards alone.
  • Get the Researching skill (×2 multiplier) before doing serious research grinding.
  • Boost Intelligence — every 8 points = +1 free research point per session, capped at 20/session total.

Time-window awareness

Watch for daylight-only locations. Royal Hunting Grounds, Townhall Uptown, Knights Training Grounds, Shopping Mall Exterior — all close at night. The Mansion Exterior is evening-only (6 PM–10 PM). Plan your travel to hit these during their hours, especially Townhall Uptown (7 AM–4 PM only, the tightest window).

Memory and performance

  • The system auto-abstracts species at 1,000+ population to keep saves manageable.
  • Old saves with bloated detailed populations are auto-converted to abstract on load via salvage_old_save_on_load.
  • The backup system also kicks in automatically once you cross 1,000 combined population + any research, providing a daily safety net against silent corruption.

Reward planning

  • The 500K and 5M crystal rewards are easy mid-game targets.
  • 1M unlocks Marina's Caterpillar Bait — permanent fishing minigame buff (unlimited bait, faster ring spawn, better rarity).
  • 10M and 15M unlock the Silken Moth Cloth maid item and Silk Uniform worker item — both go through one-time plot triggers at Whispering Woods (Medieval) specifically.
  • 100M is a long-term goal for the Secret Guardian crystal payout.

Marina caterpillar bait — unlock checklist

To unlock at the Medieval Fishing Hut, all of these must be true:

  • Marina relationship at "Acknowledged" stage or higher
  • Combined ecosystem total at 1,000,000+
  • At Marina's hut during her hours (4 AM – 5 PM)

The action shows up automatically once requirements are met. Single use; permanent buff after.

Hiking as a completion tool

Use Hike Mountains (Present, Mountains Uptown) and Climb Mountain (Medieval, Mountain Foothills) as a fast supplement to clickable spawns. Since both pull equally from every species in every pool of the current era, rare species in long-respawn pools (Witch's Hut Atlas, Bandit Hideout Death's-head) become reachable without waiting on the cooldown. Switch eras to fish for both era's species across hiking sessions.

Brothel Garden exclusive species

Owning a brothel unlocks the Brothel Garden as a caterpillar spawn point — exclusive to Lime Hawkmoth (20) and Poplar Hawkmoth (22). These two species don't appear anywhere else in the game, making brothel ownership a soft gate for a 100% collection.

This guide will continue to expand. Sections currently flagged for further detail:

  • Detailed silk crafting / fabric usage chain (which fabrics craft which clothing items)
  • Screenshots for each habitat / research / detailed-population screen
Community discoveries

These official guides track the current game. The player-maintained wiki may contain additional strategies and discoveries.

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