DOI: 10.5061/dryad.m37pvmd8r
title: Low sex drive and choosy females: Fungal infections are a reproductive downfall for male house flies

description: Many entomopathogenic fungi cause infections that kill their insect host.
 Little is understood about changes in the reproductive investment that
 occur during an infection by a lethal disease over the waning life of an
 insect. Life history theory suggests the host will respond by investing
 resources into fighting the disease or increasing reproduction. Here, we
 investigate how the reproductive life of adult house flies, Musca
 domestica, is impacted by its host-specific fungal pathogen, Entomophthora
 muscae. Specifically, we test how the week-long infection alters the
 mating behavior of virgin adult male house flies. We find that the
 pathogen significantly decreases male libido; an effect which grows
 stronger over the course of the infection. Furthermore, females were
 significantly less likely to choose an infected male, reducing male mating
 success. Additionally, we assessed sperm viability to understand the
 reproductive costs for monandrous females to mate with infected males.
 Analyses revealed that sperm quality decreases as early as three days
 post-infection. These results show that E. muscae, which can have a
 prevalence near 100% in wild populations, causes severe lifetime
 reproductive costs to male house flies. Understanding how host-pathogen
 interactions affect host life history is crucial for elucidating all the
 negative effects pathogen virulence exerts on hosts.
description: # Low sex drive and choosy females: Fungal infections are a reproductive
 downfall for male house flies
 There are nine annotated
 datasets: Activity.csv, Male_Housefly_Weight.csv, Virulence.csv,
 MatingLatency.csv, FemaleChoice.csv, Mating_Attempts_Duration.csv,
 SpermViability.csv ## Description of the data and file structure The
 Activity.csv dataset was used in locomotion analyses and to generate
 Figures 1a, S3a and S4. Table of contents for Activity.csv * Individual:
 unique ID formed of the concatenation of variables Subject, Time and Week
 (see below) - (this variable was not used in this study) * Subject: ID
 code for for each individual fly per weekly batch, indicating treatment
 status (infected or control) and its assigned number - (this variable was
 not used in this study) * Time: number of hours after house flies were
 first placed with sporulating or freeze-killed cadavers * Video: video
 number of the day, where 1 = 9am, 2 = noon and 3 = 3pm * dpi: day post
 infection of data collection (from 2 to 7) * Week: batch used in data
 collection organised by separate weeks of filming * BeforeDeath: number of
 hours before experimental house flies died (inverse of Time) *
 DayReversed: dpi in reverse chronological order, from death to infection.
 * Observation: experimental treatment based on health status: control (=
 uninfected) or infected * deathday: experimental treatment based on health
 status and which day house flies died: control (= uninfected), DeadDay6
 (infected flies that died 6 days post infection) and DeadDay7 (infected
 flies that died 7 days post infection) * locomotion.no: number of
 performed locomotion events * locomotion.dur: duration (in seconds) of
 performed locomotion events * standing.still.no: number of static (no
 discernible behavior) events - (these data were not used in this study) *
 standing.still.dur: duration (in seconds) of static (no discernible
 behavior) events - (these data were not used in this study) * drinking.no:
 number of performed drinking events - (these data were not used in this
 study) * drinking.dur: duration (in seconds) of performed drinking events
 - (these data were not used in this study) * feeding.no: number of
 performed feeding events - (these data were not used in this study) *
 feeding.dur: duration (in seconds) of performed feeding events - (these
 data were not used in this study) * grooming.no: number of performed
 grooming events - (these data were not used in this study) * grooming.dur:
 duration (in seconds) of performed grooming events - (these data were not
 used in this study) The Male_Housefly_Weight.csv dataset was used in
 virulence analyses and to generate Figures 1b and S3b. Table of contents
 for Male_Housefly_Weight.csv * Date: date of data collection * Treatment:
 experimental treatment based on health status: control (= uninfected) or
 infected * dpi: day post infection of data collection (from 2 to 6) * Age:
 age in days as adult flies at time of measurement * ID: ID code for each
 fly used in each trial * Trial_ID: Trial number * weight_ug: fly weight in
 micrograms (ug) * weight_mg: fly weight in milligrams (mg) The
 Virulence.csv dataset was used in virulence analyses and to generate
 Figure 1c. Table of contents for Virulence.csv * Treatment: experimental
 treatment based on health status: control (= uninfected) or infected *
 Pupae_date: date of pupation * Age: age in days as adult flies at time of
 measurement * infection_date: date of exposure to sporulating or
 freeze-killed cadavers * Pot: experimental container number * dpi: day
 post infection of data collection (from 1 to 7) * FlyID: ID code for each
 of the 10 flies per container (from 1 to 10) * Status: mortality status
 0=alive, 1=dead (binary 0/1) The MatingLatency.csv dataset was used in
 male mating latency analyses and to generate Figures 2a-c. Table of
 contents for MatingLatency.csv * Observation: unique ID code for each
 behavioural assay * Age: age in days as adult flies at time of measurement
 * dpi: day post infection of data collection (from 2 to 6) * TimeOfDay:
 time of day of behavioural assay (AM = morning, PM = afternoon) *
 Treatment: experimental treatment based on health status: control (=
 uninfected) or infected * Mated_not: mating status - unmated or mated *
 status: mating status 0=unmated, 1=mated (binary 0/1) * matinglatency_sec:
 male mating latency measured as time in seconds taken to successfully mate
 following arousal from anaethesia * matinglatency_minute: male mating
 latency measured as time in minutes taken to successfully mate following
 arousal from anaethesia The FemaleChoice.csv dataset was used in female
 choice analyses and to generate Figures 2d-f. Table of contents for
 FemaleChoice.csv * Observation: unique ID code for each behavioural assay
 - (same as in MatingLatency.csv) * Age: age in days as adult flies at time
 of measurement - (same as in MatingLatency.csv) * dpi: day post infection
 of data collection (from 2 to 6) - (same as in MatingLatency.csv) *
 TimeOfDay: time of day of behavioural assay (AM = morning, PM = afternoon)
 - (same as in MatingLatency.csv) * Treatment: experimental treatment based
 on health status: control (= uninfected) or infected - (same as in
 MatingLatency.csv) * Mated_not: mating status - unmated or mated - (same
 as in MatingLatency.csv) * mateattempts: number of mating attempted by the
 male * status: mating status 0=unmated, 1=mated (binary 0/1) - (same as in
 MatingLatency.csv) * femchoice_sec: female choice measured as time in
 seconds taken for a female to accept a male that has attempted to mate
 (flies that did not attempt to mate (i.e. mateattempts = 0, were removed
 during analyses)) * femchoice_minute: female choice measured as time in
 minutes taken for a female to accept a male that has attempted to mate
 (flies that did not attempt to mate (i.e. mateattempts = 0, were removed
 during analyses)) The Mating_Attempts_Duration.csv dataset was used in the
 analyses of male number and duration of courtship attempts and of mating
 duration, and to generate Figures 3 and S6. Table of contents for
 Mating_Attempts_Duration.csv * Observation: unique ID code for each
 behavioural assay - (same as in MatingLatency.csv) * Age: age in days as
 adult flies at time of measurement - (same as in MatingLatency.csv) * dpi:
 day post infection of data collection (from 2 to 6) - (same as in
 MatingLatency.csv) * TimeOfDay: time of day of behavioural assay (AM =
 morning, PM = afternoon) - (same as in MatingLatency.csv) * weight_mg: fly
 weight in milligrams (mg) * Treatment: experimental treatment based on
 health status: control (= uninfected) or infected - (same as in
 MatingLatency.csv) * Mated_not: mating status - unmated or mated - (same
 as in MatingLatency.csv) * active.no: an active behaviour was scored when
 the male awoke from anaethesia and initiated the start of the trial for a
 male/female pair * mounting.no: number of performed mount events *
 repeat_courtship.no: number of performed repeat courtship events *
 dismount.no: number of performed dismount events * mating.no: number of
 performed mating events * separated.no: a separated event indicates the
 end of the trial for a male/female pair - either by end of a mating event
 or by withdrawl from the experiment for unmated pairs * active.dur:
 duration from when the male awoke from anaethesia to performance of a
 scored behaviour * mounting.dur: duration of performed mount events *
 repeat_courtship.dur: duration of performed repeat courtship events *
 dismount.dur: duration of performed dismount events * mating.dur: duration
 of performed mating events * persist.no: total number of performed
 courtship behaviours (calculated as the sum of count.no and
 repeat_courtship.no) * persist.dur: total duration of performed courtship
 behaviours (calculated as the sum of count.dur and repeat_courtship.dur)
 The SpermViability.csv dataset was used in sperm viability analyses and to
 generate Figures 4a and S7. Table of contents for SpermViability.csv *
 Date: date of data collection * FlyID: unique ID code for each individual
 * dpi: day post infection of data collection (from 2 to 6) * Age: age in
 days as adult flies at time of measurement * Treatment: experimental
 treatment based on health status: control (= uninfected) or infected -
 (same as in MatingLatency.csv) * TimeOfDay: time of day of behavioural
 assay (AM = morning, PM = afternoon) - (same as in MatingLatency.csv) *
 weight_mg: fly weight in milligrams (mg) * total_green: number of live
 sperm cells (stained green by the live/dead sperm viability kit) *
 total_red: number of dead sperm cells (stained gred by the live/dead sperm
 viability kit) * total_mixed: number of dual-stained sperm cells
 (dual-stained by the live/dead sperm viability kit) * total: total number
 of sperm cells * pct_green: percent of live sperm cells (stained green by
 the live/dead sperm viability kit) measured as 100*total_green/total *
 pct_red: percent of dead sperm cells (stained gred by the live/dead sperm
 viability kit) measured as 100*total_red/total * pct_mixed: percent of
 dual-stained sperm cells (dual-stained by the live/dead sperm viability
 kit) measured as 100*total_mixed/total ## Code/Software The R markdown
 file Edwards_et_al_2024_Libido_and_FemaleChoice.Rmd can be used to run all
 reported analyses and generate all published figures. The knitted version
 of the R markdown file Edwards_et_al_2024_Libido_and_FemaleChoice.html can
 be used to view all reported analyses.