DOI: 10.5061/dryad.ngf1vhj1v
title: Fertility loss under thermal stress

description: Climate change models predict that the frequency and intensity of
 heatwaves are likely to increase, therefore understanding population
 responses to these extreme climatic events will be key in mitigating
 biodiversity loss. Here, using the male dimorphic bulb mite, Rhizoglyphus
 robini, we investigate and compare the impact of experimental heat stress
 on survival and fertility between females and male morphs that differ in
 the expression of a sexually selected weapon. We show that lethal limits
 are similar among all individuals, but find clear sex differences,
 although no difference between morphs, in sub-lethal temperatures causing
 sterility: female fertility remains high close to lethal limits, whereas
 both male morphs suffer fertility loss at more than 2.5°C below their
 lethal limits. Contrastingly, when thermal stress was lower, the sexes and
 morphs do not differ in their thermal sensitivity and declines in
 reproductive output are comparable, these declines appear to be additive
 as we observe the greatest declines when both sexes were exposed to
 thermal stress. In addition, during assays, we included an extra treatment
 that allowed individuals two extra days to recover and found that
 fertility loss was almost fully recovered when thermal stress was low, but
 only partially recovered under the most extreme temperatures. The impact
 of heat stress on fertility therefore appears to be temporary with
 individuals rapidly recovering: whether recovery can negate negative
 population level effects remains to be investigated. Our experiments
 reveal the impact of heat stress on survival and fertility, finding
 sex-specific fertility loss under the most extreme thermal conditions.
description: Individual mites were isolated from a large outbred stock
 population. These individuals were then exposed to varying levels of
 thermal stress (or control temperatures). These focal individuals were
 then paired with individuals of the opposite sex that has not been exposed
 to heat stress for 2 days and allowed to mate and produce offspring. We
 also included an addiontal treatment that allowed heat stressed
 individuals an addiontal 2 days to recover from heat stress prior to
 pairing. We scored fertility loss in two ways: 1) thermal fertility limits
 was estimated by scoring focals as fertile or not by the presence/absence
 or any number of larvae produced and 2) thermal sensetivity of fertility
 was estimated by counting the number of offspring produced by pairs.
 Addiionally we calculated thermal limits by scoring individuals as dead or
 alive after heat stress. Thermal limits and thermal
 fertility limits were analysed using dose response models and thermal
 sensetivity of fertility was analysed using hurdle models due to zero
 inflation in these data.
description: ### Death\_data.csv Data describes the counts of individuals alive and
 dead after being exposed to varying levels of two day heat stress column
 description: * Focal - categorical factor describing sex and morph of the
 individual, either: Female, Fighter (male) or Scrambler (male) * Block -
 factor describing the block that the experiment was performed, either: 1
 or 2 * Temp - the temperature (C) focal individuals were exposed to,
 either: 23 degrees (control) or 29-36 degrees * Alive - count of
 individuals that were alive after heat stress * Dead - count of
 individuals that were dead after heat stress * Error - count of
 individuals that were discarded due to various errors, such as:
 experimenter handling error or vials being considered to have low humidity
 #### ### TFL\_data.csv Data describing the counts of individuals scored as
 fertile or not after being exposed to varying levels of two day heat
 stress *Note* Females were paired with both male morphs and data is
 separate here, but all analysis was performed by the combination of these.
 As a consequence of keeping these data separate there are large blocks of
 NA's in the Larvae_S_male, No_larvae_S_male and
 No_Larvae_death_S_male columns because in these cases the focal
 individual's were either fighter or scrambler males i.e. these
 columns are only used when a focal female was paired with a scrambler
 male. We also scored vials in which the focal died during the egg laying
 period and did not produce larvae, these were not included in analysis.
 column description: * Block - factor describing the block that the
 experiment was performed, either: 1 or 2 * Recovery - factor describing
 whether the focal individuals were given an additional two day recovery
 period, either: Yes or No * Focal - categorical factor describing sex and
 morph of the individual, either: Female, Fighter (male) or Scrambler
 (male) * Temp - the temperature (C) focal individuals were exposed to,
 either: 23 degrees (control) or 29-36 degrees * Larvae - Count of vials in
 which larvae were present (females paired with fighter males) * No_larvae
 - Count of vials which had no larvae (females paired with fighter males) *
 No_Larvae_death - Count of vials in which there were no larvae but the
 focal individual was found dead (females paired with fighter males) *
 Larvae - Count of vials in which larvae were present (females paired with
 fighter males) * No_larvae - Count of vials which had no larvae (females
 paired with fighter males) * No_Larvae_death - Count of vials in which
 there were no larvae but the focal individual was found dead (females
 paired with fighter males) * Larvae_S_male - Count of vials in which
 larvae were present (females paired with scrambler males) *
 No_larvae_S_male - Count of vials which had no larvae (females paired with
 scrambler males) * No_Larvae_death_S_male - Count of vials in which there
 were no larvae but the focal individual was found dead (females paired
 with scrambler males) * Error - count of individuals that were discarded
 due to various errors, such as: experimenter handling error or vials being
 considered to have low humidity ##### ### TSF\_data.csv Data describing
 the counts of larvae produced by pairs after being exposed to varying
 levels of two day heat stress column description: * Recovery - factor
 describing whether the focal individuals were given an additional two day
 recovery period, either: Yes or No * Block - factor describing the block
 that the experiment was performed, either: 1 or 2 * Female_temp - factor
 describing whether the female in the pair was exposed to heat stress or
 not, either: F-23 (23 degrees) or F-30 (30 degrees) * Male_temp - factor
 describing whether the male in the pair was exposed to heat stress or not,
 either: M-23 (23 degrees) or M-30 (30 degrees) * Morph - factor describing
 the morph of male in each pair, either F (fighter) or S (scrambler) * ID -
 lab number of vials * Larvae - counts of larvae in each vial