DOI: 10.5061/dryad.2z34tmpxd
title: Data from: Heating up parasitoid-host interactions: high temperature increased mortality of late-instar braconid larvae and reduced ladybird recovery rate

description: With ongoing climate change, temperature-dependent outcomes of
 host-parasitoid interactions can affect ecosystem functioning and key
 ecosystem services such as biological control. However, most studies
 addressing the impacts of temperature on host-parasitoid systems are
 biased toward immature host stages and agricultural pests, specifically
 Lepidoptera. Moreover, despite their relevance for population dynamics,
 important life-history traits such as host recovery (i.e., restoring
 feeding and mating behaviour after parasitism) remain largely neglected.
 In this study we tested the effects of low (18°C), optimal (24°C), and
 high (30°C) temperatures on the development, survival, and body size of
 the braconid parasitoid Dinocampus coccinellae and longevity and recovery
 probability of its adult host, the invasive ladybird Harmonia axyridis. At
 low temperature, susceptible ladybirds, in which parasitoid larvae
 successfully developed, lived significantly shorter than resistant
 ladybirds that likely eliminated parasitoid, and control individuals lived
 significantly longer than both types of infected ladybirds. At optimal
 temperature, host survival was mainly determined by parasitoid
 development, as resistant and control ladybirds lived similarly long and
 susceptible individuals lived significantly shorter. At high temperatures
 all ladybirds exposed to the parasitoid lived significantly shorter than
 control ones. Temperature significantly affected stage-specific mortality
 of parasitoids, with significantly higher proportion of late larval instar
 dying at high temperature. This together with increased pupal mortality
 resulted in inability of Dinocampus coccinellae to complete development at
 30°C. Ladybird recovery was significantly affected by temperature, host
 sex and their interaction, showing highest values at optimal temperature
 for both sexes, but strongly decreased male recovery at low temperature.
 In addition, host sex influenced parasitoid body size: female ladybirds
 produced larger adult wasps. The combined effects of high temperatures and
 parasitism negatively affected host life-history traits, with extreme
 temperatures also mediating cascading effects on its braconid
 endoparasitoid. We demonstrate how temperature- and stage-specific
 parasitoid mortality can influence host longevity and the understudied
 recovery probability, focusing on an adult beetle host, providing novel
 information for climate change ecology of host-parasitoid interactions.
description: <strong>Experimental animals</strong>
 Harmonia axyridis ladybirds were collected during autumn 2022 in
 Prague and successfully overwintered under semi-natural conditions, i.e.,
 groups of ladybirds in glass jars with perforated lids were placed under
 shrubby vegetation in the university campus. In mid-April 2023 ladybirds
 were sorted into males and females in the laboratory. After several days,
 we established 10 parental pairs to produce offspring for the laboratory
 experiment. Other ladybirds formed single-sex groups (8-12 individuals per
 Petri dish). All ladybirds were reared at 24°C, 16L:8D photoperiod and
 provided with food (Ephestia kuehniella eggs) and water ad libitum for
 three weeks. Offspring (larvae) produced by parental pairs were also
 reared in the same conditions as their parents. By rearing the ladybirds
 from eggs in the laboratory, we ensured that the individuals used in the
 subsequent laboratory experiment were free of infection by Dinocampus
 coccinellae. Single-sex groups were reared with the
 goal of gathering D. coccinellae wasps, which frequently emerge from
 overwintering ladybirds during spring. Wasps obtained from the original
 hosts were allowed to infect novel ladybird hosts in the laboratory to get
 the next generation of parasitoids that will emerge in early June.
 Original overwintered H. axyridis females were used as novel hosts for
 this purpose. In total, we acquired over 60 Dinocampus wasps and 50 of
 them were used for our laboratory experiment. Each wasp was kept
 separately in a Petri dish and provided with honey dissolved in water to
 maximize parasitoid longevity and fecundity.
 <strong>Laboratory experiment</strong>
 The sex of each offspring ladybird was determined ca. 24 hours
 after eclosion from pupae, and ladybirds were accommodated individually in
 Petri dishes and provided with ad libitum food as described above. When
 experimental ladybirds were ca. 14 days old (early June 2023), a subset
 was exposed to Dinocampus wasps, resulting in either a development of
 parasitoid larvae (‘infected with larvae’ treatment) or unsuccessful
 larval development (‘infected without larvae’ treatment). The remaining
 subset, unexposed to Dinocampus wasps, were considered control individuals
 (‘control’ treatment, see details below). Each ladybird from infected
 treatments was exposed to 3-5 different wasps in a single day to maximize
 infection success. The same wasps were re-utilized for several days to
 infect multiple ladybirds. Immediately after infection (or during that day
 for control individuals), ladybirds were placed to three temperature
 regimes: 18°C (low), 24°C (optimal) and 30°C (high), resulting in nine
 groups in total (infected with larvae, infected without larvae and control
 treatments at each temperature). During the following
 days, we recorded the presence of D. coccinellae pupae, the emergence of
 adult parasitoids and the survival of ladybirds in each Petri dish daily.
 For ladybirds from which D. coccinellae pupa emerged and stayed paralyzed
 we recorded if they recovered from the paralysis, i.e., whether they
 started to move and feed. Every second day, we provided all alive
 ladybirds with ad libitum food and water. We cleaned all Petri dishes when
 needed (at least once per week). Dead ladybirds were stored in a freezer
 at -20°C and dissected at the end of the experiment to check the potential
 presence of D. coccinellae larvae and to determine the developmental stage
 of the parasitoid in the case of unsuccessful development. Finally, we
 categorized three host statuses: infected with larvae, for ladybirds
 exposed to D. coccinellae that developed a larva (either because a D.
 coccinellae larvae was found during dissection or because we observed a
 larvae emerging from the hosts’ body); infected without larvae, for
 ladybirds exposed to D. coccinellae, but no larvae were found during
 dissection (possibly related to defense mechanisms eliminating the
 parasite during the egg stage); and control, for ladybirds not exposed to
 D. coccinellae at all. It should be noted that when we dissected the
 ladybirds, we found different larval stages, so from now on we will refer
 as early stage (L1-L2): small, yellow 1st and 2nd instar larvae with
 mandibles (given the morphological similarities and the low number of
 observations, we merged these two first instars into one category for
 further analysis), 3rd instar (L3): large yellowish larvae without
 mandibles, and brownish 3rd instar (L3b): large brownish larvae without
 mandibles. L3b could be either the final stage (prepupa) that was unable
 to exit the host or dead L3 that started to be melanized due to host’s
 immune system response. For all D. coccinellae adults produced in our
 laboratory experiment, we measured their structural body size, i.e., the
 width and height of the left wing and the length of the right hind
 tibia.
description: # Data from: Heating up parasitoid-host interactions: high temperature
 increased mortality of late-instar braconid larvae and reduced ladybird
 recovery rate
 [https://doi.org/10.5061/dryad.2z34tmpxd](https://doi.org/10.5061/dryad.2z34tmpxd) ## Description of the data and file structure See metadata sheet in each dataset file for details All corresponding R script files share the name with the dataset files (just without "_data" at the end). Basic information: ### dataset_heating_up_R1_data complete dataset including all particular datasets listed below ### Dino_body_size_data Effects of temperature and ladybird (host) sex on Dinocampus (parasitoid) structural body size **variables** Lad_ID: unique ID of host individual (ladybird Harmonia axyridis) Temp: Temperature regime (18, 24 or 30 °C) Sex: Sex of the host individual (ladybird); M = male, F = female Dcoc_size_wing_length: parasitoid (Dinocampus coccinellae) front wing length in micrometers Dcoc_size_wing_width:parasitoid (Dinocampus coccinellae) front wing width in micrometers Dcoc_size_tibia: parasitoid (Dinocampus coccinellae) right hind tibia length in micrometers ### Dino_developmental_stages_data Effects of Dinocampus (parasitoid) development stage, temperature and host sex on ladybird (host) longevity **variables** Lad_ID: unique ID of host individual (ladybird Harmonia axyridis) Sex: Sex of the host individual (ladybird); M = male, F = female Temp: Temperature regime (18, 24 or 30 °C) Ladybird_longevity Ladybird longevity (days) Dino_stage: Stages of Dinocampus coccinellae: NL (no larva = development stopped at the egg stage); L1-L2, L3, L3b (larval stages - all stages within the host); and pupae and adult (observable outside the host) ### Dino_developmental_time_data Effects of temperature and ladybird (host) sex on Dinocampus (parasitoid) larval and pupal developmental time **variables** Lad_ID: unique ID of host individual (ladybird Harmonia axyridis) Sex: Sex of the host individual (ladybird); M = male, F = female Temp: Temperature regime (18, 24 or 30 °C) larva_number_days: Time (days) from parasitoid infection date to first day of cocoon (pupa) pupa_number_days: Time (days) from the first day of parasitoid cocoon (pupa) to adult eclosion Dino_stage: Stages of Dinocampus coccinellae: Pupae (individuals died as pupea) and Adult (individuals developed to adults) ### Dino_success_data Effects of temperature and ladybird (host) sex on Dinocampus (parasitoid) larval and pupal developmental success variables Sex: Sex of the host individual (ladybird); M = male, F = female Temp: Temperature regime (18, 24 or 30 °C) Dino_stage: Stages of Dinocampus coccinellae: NL (no larva = development stopped at the egg stage); L1-L2, L3, L3b (all stages within the host); and pupae and adult (observable outside the host) Larvae_binom: Binary variable for successful infection by the parasitoid (1 = successfull infection; 0 = failed infection, no signs of parasitoid development) Pupae_binom: Binary variable for successful parasitoid larval development (1 = successful larva, completed their developmental stage into a pupa; 0 = unsuccessful larvae Adult_binom: Binary variable for successful parasitoid pupal development (1 = successful pupa, completed their developmental stage into an adult; 0 = unsuccessful pupa) ### LB_survival_data Effects of temperature, ladybird (host) sex and parasitoid treatment on ladybird survival (longevity) **variables** Lad_ID: unique ID of host individual (ladybird Harmonia axyridis) Sex: Sex of the host individual (ladybird); M = male, F = female Temp: Temperature regime (18, 24 or 30 °C) Status: Binary variable of survival status (0 = alive, 1 = dead). Time: Time in days between host infection and death New_treatm: Host status: Larvae = ladybirds exposed to D. coccinellae that developed a larva, NL = ladybirds exposed to D. coccinellae, but no larvae found during dissection, and Uninfected = ladybirds not exposed to D. coccinellae. ### LB_recovery_data Effects of temperature and ladybird (host) sex on ladybird recovery **variables** Lad_ID: Unique identifier for each ladybird Sex: Sex of the host individual (ladybird); M = male, F = female Temp: Temperature regime (18, 24 or 30 °C) LB_recovery_binom: Binary variable for ladybird recovery of normal behaviour after Dinocampus coccinellae pupa hatching (1= successfull recovery, 0 = no recovery) script **complete_success** works with the **Dino_developmental_stages_data.xlsx** dataset and investigate overal parazitoid success (probability of development into adult wasp)