We asked if fleas more frequently remain on those California ground squirrels (Spermophilus beecheyi) that are likely to emigrate from their natal nest. In Camp Ohlone, Alameda County, California, juvenile male squirrels were infested with more fleas (Oropsylla montana) than were juvenile females, and juveniles of both sexes were infested with more fleas (O. montana and Hoplopsyllus anomalus) than adults. There was no difference between the adult sexes in the number of fleas. The disproportionate infestation of male juveniles was accounted for almost exclusively by male O. montana. Greater activity on the part of juvenile males did not account for this difference; the activity of male and female juveniles was very similar. As yearlings, male squirrels established home ranges at greater distances from the natal burrow than did females. Remaining on ranging male squirrels might help male fleas find nonsibling mates in new nests, whereas female fleas might tend to stay in the natal nest in order to assure their progeny of its resources. Flea behavior, modified by characteristics of the host that are sex-specific and predictive of future traits, such as the tendency to range, may thus determine the nature and extent of infestations in juvenile squirrels.
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PLoS One
March 2025
Environmental Science Program, Memorial University of Newfoundland, Corner Brook, Canada.
Territorial responses by North American red squirrels (Tamiasciurus hudsonicus) to conspecifics vary seasonally with peaks during mating and dispersal periods. Broadcast of squirrel vocalizations during surveys may elicit territorial defense behaviors such as calling and movement that make individuals more available for detection, with implications for subsequent occupancy and abundance analyses. We examined the effect of vocalization broadcasts on detection probability during point counts throughout a 14-month period at two locations (year-round study) and during two summers at a third location (summer-only study) on Newfoundland, Canada.
View Article and Find Full Text PDFVet Parasitol Reg Stud Reports
February 2025
Warnell School of Forestry and Natural Resources, UGA, University of Georgia, 180 E Green St., Athens, GA 30602, USA; Southeastern Cooperative Wildlife Disease Study Laboratory, The University of Georgia, Athens, GA, USA; Center for Emerging Infectious Diseases, Athens, GA, 30602, USA. Electronic address:
Toxoplasmosis is a parasitic disease that exemplifies the One Health interface due to its global distribution and diversity of hosts in which it can infect and potentially cause disease. While T. gondii, the causative agent of toxoplasmosis, has been well-described in many wildlife taxa, including wild and domestic birds and mammals, there is limited published research on clinical disease in wild lagomorphs and rodents.
View Article and Find Full Text PDFNeuropsychopharmacology
February 2025
Behavioral Biology Program, McLean Hospital, Belmont, MA, USA.
Adolescent cannabinoid exposure has been implicated in enduring modifications to adult brain circuitry; however, well-controlled, systematic analyses investigating dose-dependent effects of chronic delta-9-tetrahydrocannabinol (THC) exposure on brain connectivity are lacking. It is hypothesized that large-scale intrinsic networks, such as default mode (DMN), central executive (CEN), and salience networks (SN), are critically involved in vulnerability to deficits in cognitive processing often associated with adolescent cannabis use. The present study aimed to elucidate the effects of chronic THC exposure on functional connectivity (FC) of these putative large-scale networks in nonhuman primates.
View Article and Find Full Text PDFSci Rep
February 2025
Laboratory of Molecular Biology, Department of Biosciences, School of Science, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara-shi, Kanagawa, 252-0373, Japan.
Circadian rhythms play an important role in many physiological processes. We have previously reported that no periodic fluctuation in the Bmal1 mRNA is observed in the liver of the chipmunk, a mammalian hibernator, in the hibernation season, suggesting that peripheral circadian clocks are not functional during hibernation. In contrast, the Per2 mRNA levels are transiently increased by elevated body temperature during interbout arousal and showed periodic fluctuations in the hibernation season, suggesting that periodic expression of the Per2 mRNA may be restored during interbout arousal.
View Article and Find Full Text PDFCan Vet J
February 2025
Veterinary Biomedical Sciences, Western College of Veterinary Medicine, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4.
Background: Strychnine is a highly toxic, plant-derived alkaloid. It has historically been used in western Canada as a rodenticide for control of Richardson's ground squirrels; and in Alberta, as a predacide against wolves, coyotes, black bears, and skunks. However, nontarget species poisonings with strychnine have been widely documented in Canada and elsewhere.
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