Spatial and temporal complexities of reproductive behavior and sex ratios

A case from parasitic insects

Katharina Dittmar, Solon Morse, Matthew E. Gruwell, Jason Mayberry, Emily DiBlasi

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Background: Sex ratios are important empirical data in predicting sex allocation strategy and selection in populations. Therefore, they should be sampled at crucial developmental steps before and after parental investment. In parasites with free-living (off-host) developmental stages the timing and method of sampling is not trivial, because ecological niches are frequently poorly known. Consequently, information is scarce for sex ratios of these parasites between conception and sexual maturity. Often, only data from adult parasites are available, which usually were collected from the parasite's hosts. Generally, these ratios are assumed to represent operational sex ratios. Methodology/Principal Findings: We here report three years of empirical data on population sex differentials from a bat ectoparasite (Trichobius frequens) with off-host developmental stages. At emergence these parasites exhibit a significant and seasonally stable female biased sex ratio. This bias is lost in the adult population on the roosting host, which shows sex ratios at equality. This is best explained by a behaviorally driven, sex-dependent mortality differential. Because consistently only subsets of females are available to mate, the operational sex ratio in the population is likely male biased. Host capture experiments throughout the day show a statistically significant, but temporary male excess in bat flies on foraging bats. This phenomenon is partly driven by the diurnal rhythms of female larviposition, and partly due to parasites remaining in the bat roost during foraging. Because most previous research in bat flies is based only on foraging bats, female contributions to physical sex ratios have been underestimated. Conclusion/Significance: Our results highlight the importance of detailed natural history observations, and emphasize that ignoring the spatial and temporal heterogeneity of reproduction in any organism will lead to significant empirical sampling errors of sex ratios, and may obscure operational sex ratios.

Original languageEnglish (US)
Article numbere19438
JournalPLoS One
Volume6
Issue number5
DOIs
StatePublished - May 17 2011

Fingerprint

Reproductive Behavior
Sex Ratio
reproductive behavior
parasitoids
Insects
sex ratio
Parasites
parasites
Chiroptera
Streblidae
foraging
Sampling
Diptera
Population
larviposition
developmental stages
sex allocation
Selection Bias
gender
ectoparasites

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

Dittmar, Katharina ; Morse, Solon ; Gruwell, Matthew E. ; Mayberry, Jason ; DiBlasi, Emily. / Spatial and temporal complexities of reproductive behavior and sex ratios : A case from parasitic insects. In: PLoS One. 2011 ; Vol. 6, No. 5.
@article{3cfe1ea797874d948cfe85672dd6015b,
title = "Spatial and temporal complexities of reproductive behavior and sex ratios: A case from parasitic insects",
abstract = "Background: Sex ratios are important empirical data in predicting sex allocation strategy and selection in populations. Therefore, they should be sampled at crucial developmental steps before and after parental investment. In parasites with free-living (off-host) developmental stages the timing and method of sampling is not trivial, because ecological niches are frequently poorly known. Consequently, information is scarce for sex ratios of these parasites between conception and sexual maturity. Often, only data from adult parasites are available, which usually were collected from the parasite's hosts. Generally, these ratios are assumed to represent operational sex ratios. Methodology/Principal Findings: We here report three years of empirical data on population sex differentials from a bat ectoparasite (Trichobius frequens) with off-host developmental stages. At emergence these parasites exhibit a significant and seasonally stable female biased sex ratio. This bias is lost in the adult population on the roosting host, which shows sex ratios at equality. This is best explained by a behaviorally driven, sex-dependent mortality differential. Because consistently only subsets of females are available to mate, the operational sex ratio in the population is likely male biased. Host capture experiments throughout the day show a statistically significant, but temporary male excess in bat flies on foraging bats. This phenomenon is partly driven by the diurnal rhythms of female larviposition, and partly due to parasites remaining in the bat roost during foraging. Because most previous research in bat flies is based only on foraging bats, female contributions to physical sex ratios have been underestimated. Conclusion/Significance: Our results highlight the importance of detailed natural history observations, and emphasize that ignoring the spatial and temporal heterogeneity of reproduction in any organism will lead to significant empirical sampling errors of sex ratios, and may obscure operational sex ratios.",
author = "Katharina Dittmar and Solon Morse and Gruwell, {Matthew E.} and Jason Mayberry and Emily DiBlasi",
year = "2011",
month = "5",
day = "17",
doi = "10.1371/journal.pone.0019438",
language = "English (US)",
volume = "6",
journal = "PLoS One",
issn = "1932-6203",
publisher = "Public Library of Science",
number = "5",

}

Spatial and temporal complexities of reproductive behavior and sex ratios : A case from parasitic insects. / Dittmar, Katharina; Morse, Solon; Gruwell, Matthew E.; Mayberry, Jason; DiBlasi, Emily.

In: PLoS One, Vol. 6, No. 5, e19438, 17.05.2011.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Spatial and temporal complexities of reproductive behavior and sex ratios

T2 - A case from parasitic insects

AU - Dittmar, Katharina

AU - Morse, Solon

AU - Gruwell, Matthew E.

AU - Mayberry, Jason

AU - DiBlasi, Emily

PY - 2011/5/17

Y1 - 2011/5/17

N2 - Background: Sex ratios are important empirical data in predicting sex allocation strategy and selection in populations. Therefore, they should be sampled at crucial developmental steps before and after parental investment. In parasites with free-living (off-host) developmental stages the timing and method of sampling is not trivial, because ecological niches are frequently poorly known. Consequently, information is scarce for sex ratios of these parasites between conception and sexual maturity. Often, only data from adult parasites are available, which usually were collected from the parasite's hosts. Generally, these ratios are assumed to represent operational sex ratios. Methodology/Principal Findings: We here report three years of empirical data on population sex differentials from a bat ectoparasite (Trichobius frequens) with off-host developmental stages. At emergence these parasites exhibit a significant and seasonally stable female biased sex ratio. This bias is lost in the adult population on the roosting host, which shows sex ratios at equality. This is best explained by a behaviorally driven, sex-dependent mortality differential. Because consistently only subsets of females are available to mate, the operational sex ratio in the population is likely male biased. Host capture experiments throughout the day show a statistically significant, but temporary male excess in bat flies on foraging bats. This phenomenon is partly driven by the diurnal rhythms of female larviposition, and partly due to parasites remaining in the bat roost during foraging. Because most previous research in bat flies is based only on foraging bats, female contributions to physical sex ratios have been underestimated. Conclusion/Significance: Our results highlight the importance of detailed natural history observations, and emphasize that ignoring the spatial and temporal heterogeneity of reproduction in any organism will lead to significant empirical sampling errors of sex ratios, and may obscure operational sex ratios.

AB - Background: Sex ratios are important empirical data in predicting sex allocation strategy and selection in populations. Therefore, they should be sampled at crucial developmental steps before and after parental investment. In parasites with free-living (off-host) developmental stages the timing and method of sampling is not trivial, because ecological niches are frequently poorly known. Consequently, information is scarce for sex ratios of these parasites between conception and sexual maturity. Often, only data from adult parasites are available, which usually were collected from the parasite's hosts. Generally, these ratios are assumed to represent operational sex ratios. Methodology/Principal Findings: We here report three years of empirical data on population sex differentials from a bat ectoparasite (Trichobius frequens) with off-host developmental stages. At emergence these parasites exhibit a significant and seasonally stable female biased sex ratio. This bias is lost in the adult population on the roosting host, which shows sex ratios at equality. This is best explained by a behaviorally driven, sex-dependent mortality differential. Because consistently only subsets of females are available to mate, the operational sex ratio in the population is likely male biased. Host capture experiments throughout the day show a statistically significant, but temporary male excess in bat flies on foraging bats. This phenomenon is partly driven by the diurnal rhythms of female larviposition, and partly due to parasites remaining in the bat roost during foraging. Because most previous research in bat flies is based only on foraging bats, female contributions to physical sex ratios have been underestimated. Conclusion/Significance: Our results highlight the importance of detailed natural history observations, and emphasize that ignoring the spatial and temporal heterogeneity of reproduction in any organism will lead to significant empirical sampling errors of sex ratios, and may obscure operational sex ratios.

UR - http://www.scopus.com/inward/record.url?scp=79955895609&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79955895609&partnerID=8YFLogxK

U2 - 10.1371/journal.pone.0019438

DO - 10.1371/journal.pone.0019438

M3 - Article

VL - 6

JO - PLoS One

JF - PLoS One

SN - 1932-6203

IS - 5

M1 - e19438

ER -