DOI: 10.5061/dryad.6q573n638
title: Heat knock-down times of urban and rural Chiasmia clathrata moth larvae and adults

description: Urbanization and its urban‐heat‐island effect (UHI) have expanding
 footprints worldwide. The UHI means that urban habitats experience a
 higher mean and more frequent extreme high temperatures than rural
 habitats, impacting the ontogeny and resilience of urban biodiversity.
 However, many organisms occupy different microhabitats during different
 life stages and thus may experience the UHI differently across their
 development. While evolutionary changes in heat tolerance in line with the
 UHI have been demonstrated, it is unknown whether such evolutionary
 responses can vary across development. Here, using common‐garden‐reared
 Chiasmia clathrata moths from urban and rural populations from three
 European countries, we tested for urban evolution of heat shock tolerance
 in two life stages: larvae and adults. Our results indicate widespread
 urban evolution of increased heat tolerance in the adult stage only,
 suggesting that the UHI may be a stronger selective agent in adults. We
 also found that the difference in heat tolerance between urban and rural
 populations was similar to the difference between Mid‐ and North‐European
 regions, suggesting similarity between adaptation to the UHI and natural,
 latitudinal temperature variation. Our observations incentivize further
 research to quantify the impact of these UHI adaptations on fitness during
 urbanization and climate change, and to check whether life‐stage‐specific
 adaptations in heat tolerance are typical of other ectothermic species
 that manage to survive in urbanized settings.
description: From a total of 50 different F2 and F3 full-sib moth families,
 688 individuals were tested. Of these, 82 were tested at the larval stage
 only, 81 were tested both as larvae and adults, and 525 individuals were
 tested at the adult stage only, which resulted overall in 769 heat
 knock-down measurements. All larvae from the subset of individuals
 assessed at the larval stage (N=163) were tested two days after entering
 the final (fifth) larval instar. For increased precision, each individual
 was tested separately. Each of them was weighed (Precisa 202A; precision:
 0.1 mg) immediately prior to the heat knock-down time (HKDT) measurement.
 After weighing, each individual was placed in a plastic, conical
 centrifuge tube (Falcon, 50 ml) without lid. This tube was then fully
 immersed, except for the top of the tube, in a programmable water bath
 (Grant Instruments Inc., Cambridge, UK: GD100) kept at 50.0°C for the
 duration of the experiment. The tube was held in place vertically by
 manually pressing it down to the bottom. The HKDT was recorded with a
 timer as the time in seconds from tube insertion into the bath until the
 main part of the larval body (i.e., the abdomen) stopped moving for a full
 20 seconds (these 20 seconds were not included into the HKDT). During the
 heat exposure, larvae initially either remained curled on the bottom for
 some seconds or immediately started crawling around, but all showed
 energetic crawling movements for some time before typically and suddenly
 being knocked down by falling motionless on their back. Immediately
 afterwards, larvae were placed back in their individual rearing cups and
 climate room, with identical rearing conditions for tested and non-tested
 larvae. Tested larvae that successfully completed pupation were retested
 as adults (N=81; i.e., 50% survival). Adults (N=606)
 followed a similar test procedure, except that they were not weighed, and
 that after placing them in the test tube now with cotton pushed into the
 conical tip to form a flat surface for the adult to stand on a transparent
 lid covered the tube to prevent escape. HKDT was recorded as the time in
 seconds from tube insertion into the bath until the individual fell on its
 side, without being able to recover a stable position for at least 20 s
 (small, trembling movements of appendages were allowed). After insertion
 in the tube, individuals typically waited around 20 to 50 s before walking
 and flying around until knock-down.
description: # **Heat knock-down times** These datasets contain heat knock-down time
 data for larvae and adults (separate files) of *Chiasmia clathrata*,
 related to the manuscript "Continent-wide parallel urban evolution of
 increased heat tolerance in a common moth" by Merckx et al. The
 datasets contain the following variables: **LARVAE dataset** Population:
 name of the local moth population of origin from both urban and rural
 populations from 4 European countries Sex: male or female (or unknown: NA)
 HKDT: heat knock-down time in s family: family ID number (i.e. offspring
 of same female) region: north- or mid-European origin environment: urban
 or rural origin mass: individual total body mass in mg **ADULTS dataset**
 Source: experimental source of the tested adults: HKDT, ALAN, Dark room,
 Immuno, Stock Population: name of the local moth population of origin from
 both urban and rural populations from 4 European countries Age: age in
 days HKDT: heat knock-down time in s Tested.as.larva: yes or no family:
 family ID number (i.e. offspring of same female) region: north- or
 mid-European origin environment: urban or rural origin country: country of
 origin (Belgium, Czech Republic, Sweden or Finland) sex: male or female