Biology subjects

Talbott, K.

Publications and source records attributed to Talbott, K..

4 recordsLinked to original sources

bioRxiv2026

Immediate and carryover reproductive costs of infection in female but not male house finches

Wildlife diseases cause well-documented and often dramatic reductions in host survival. However, the impact of infectious diseases on host reproduction remains understudied, especially with respect to effects of prior and/or current pathogen exposure on reproductive development. Here we experimentally tested how prior and/or current infection with a common bacterial pathogen, Mycoplasma gallisepticum ( MG), alters reproductive development for female versus male house finches (Haemorhous mexicanus). Finches were inoculated with either MG or sterile media while in wintering condition and subsequently received one of these treatments while in breeding condition. In females, MG exposure had both immediate and carry-over effects on reproduction: controls had higher odds of laying eggs compared to females inoculated with MG in spring only, higher odds than females inoculated in both winter and spring, and higher odds than females given MG in the winter only. Conversely, breeding-condition males inoculated with MG in spring had higher testosterone levels than males receiving only control inoculations, and there were no carryover effects of winter MG inoculation or inoculations during both seasons on testosterone. Sex bias in the reproductive impacts of infectious diseases may have important knock-on effects on the epidemiology and population-regulating effects of pathogens, thereby warranting further study.

ecology↗

bioRxiv2025

Male songbirds show higher coccidia oocyst burdens than femalesfollowing anthelmintic treatment

In wildlife research, wild-caught vertebrates are often given anti-parasitic drugs when brought into captivity to protect animal health and reduce confounding effects of parasitic infection on research outcomes. However, the impacts of antiparasitic drugs on non-target parasite taxa are understudied, especially regarding host sex. To help address this gap, we investigated the impact of an anthelmintic medication on a protozoan gut parasite by quantifying coccidia oocyst burden in the feces of wild-caught dark-eyed juncos (Junco hyemalis) before and after two oral doses of ivermectin. Prior to treatment, males showed higher oocyst burdens than females. Following treatment, ivermectin-treated males showed larger increases in oocyst burden compared to both control males and ivermectin-treated females, while there was no difference in baseline and post-treatment oocyst burden in treated females. Our results suggest that wild-caught songbirds should be housed separately by sex during ivermectin treatment and that male enclosures should be cleaned at a relatively higher frequency due to excessive oocyst shedding. It is unclear whether increases in oocyst burden among males were attributable to helminth removal or a direct impact of ivermectin on host immune function. Further work investigating sex differences in the impact of antiparasitic drugs on non-target parasite taxa is warranted.

ecology↗

bioRxiv2025

Fitness impacts of Plasmodium vary by host age and sex in a North American songbird

Birds infected with the malaria-causing parasite Plasmodium comprise a popular model in evolutionary ecology, yet Plasmodiums impact on host survival and reproduction remains unclear in wild bird populations where Plasmodium is historically endemic. Recent research in endemic host populations shows that Plasmodium reduces survival in juveniles, but not adults. Additional research is needed to understand 1) age-based variation in the impact of Plasmodium on host reproduction, and 2) sex-based variation in the impact of Plasmodium on survival and reproduction. To this end, we leveraged a long-term dataset from a dark-eyed junco (Junco hyemalis carolinensis) population with a high prevalence of Plasmodium. Juvenile males had lower probability of Plasmodium infection than juvenile females, indicating either elevated resistance or mortality in young males before the juvenile stage. Second year females had a lower probability of infection than females of other age classes, which suggests elevated mortality in infected yearling females after their first breeding season. Model comparison did not identify a direct relationship between Plasmodium infection and adult return (a proxy of survival), yet surprisingly, females paired with infected males in the previous breeding season had a higher probability of return. There was no relationship between Plasmodium infection and juvenile return, but returners with relatively higher parasite loads as juveniles had shorter lifespans than those without juvenile infections. Among adults, Plasmodium infection did not predict fledging success or fledgling number. However, returning juncos with relatively heavier bodies and higher parasite loads as juveniles had an increased probability of breeding in their first adult year. Combined with the shorter lifespans observed in infected juveniles, this suggests a terminal investment strategy for juncos contracting Plasmodium early in life. Our results indicate that the impact of Plasmodium on host fitness likely varies by host age at first infection and may exacerbate physiologically stressful life stages.

ecology↗

bioRxiv2025

Paying upfront: successful initial infections protect against severe future infections

Understanding the consistency with which individual hosts respond to repeated pathogen exposures is crucial for accurately modeling pathogen transmission and eco-evolutionary dynamics. When hosts face repeated pathogen exposures, immune memory is expected to reduce the probability and/or severity of subsequent infections, yet it remains unclear whether individuals remain consistent in their level of response relative to others. We investigated this question in house finches (Haemorhous mexicanus) from two populations varying in history of endemism of the bacterial pathogen Mycoplasma gallisepticum (MG). Individuals were confirmed to be MG-naive at capture and then experimentally inoculated twice with MG, allowing recovery between inoculations. We then asked if host responses to the second inoculation were predicted by responses to initial inoculation, sex, or population of origin. Our results suggest that individuals were not consistent in their relative response levels; rather, a successful initial infection provided protection against a severe second infection, increasing both tolerance and resistance. While we found no population differences in response to the second inoculation, males showed higher susceptibility to the second inoculation than females. Investigating and accounting for individual variation in response to subsequent exposures may improve the precision and accuracy of transmission models for wildlife pathogens.

ecology↗