Reproductive behavior drives female space use in a sedentary Neotropical frog

Abstract

Longer-range movements of anuran amphibians such as mass migrations and habitat invasion have received a lot of attention, but fine-scale spatial behavior remains largely understudied. This gap is especially striking for species that show long-term site fidelity and display their whole behavioral repertoire in a small area. Studying fine-scale movement with conventional capture-mark-recapture techniques is difficult in inconspicuous amphibians: individuals are hard to find, repeated captures might affect their behavior and the number of data points is too low to allow a detailed interpretation of individual space use and time budgeting. In this study, we overcame these limitations by equipping females of the Brilliant-Thighed Poison Frog (Allobates femoralis) with a tag allowing frequent monitoring of their location and behavior. Neotropical poison frogs are well known for their complex behavior and diverse reproductive and parental care strategies. Although the ecology and behavior of the polygamous leaf-litter frog Allobates femoralis is well studied, little is known about the fine-scale space use of the non-territorial females who do not engage in acoustic and visual displays. We tracked 17 females for 6 to 17 days using a harmonic direction finder to provide the first precise analysis of female space use in this species. Females moved on average 1 m per hour and the fastest movement, over 20 m per hour, was related to a subsequent mating event. Traveled distances and activity patterns on days of courtship and mating differed considerably from days without reproduction. Frogs moved more on days with lower temperature and more precipitation, but mating seemed to be the main trigger for female movement. We observed 21 courtships of 12 tagged females. For seven females, we observed two consecutive mating events. Estimated home ranges after 14 days varied considerably between individuals and courtship and mating associated space use made up for ∼30% of the home range. Allobates femoralis females spent large parts of their time in one to three small centers of use. Females did not adjust their time or space use to the density of males in their surroundings and did not show wide-ranging exploratory behavior. Our study demonstrates how tracking combined with detailed behavioral observations can reveal the patterns and drivers of fine-scale spatial behavior in sedentary species.

Naive poison frog tadpoles use bi-modal cues to avoid insect predators but not heterospecific predatory tadpoles

“…Both sexes are iteroparous and polygamous (Ursprung et al 2011) within prolonged but discrete reproductive periods that Journal of Experimental Biology • Accepted manuscript coincide with the local rainy seasons (Gottsberger and Gruber, 2004). Pair formation, courtship, and mating take place in the male's territory (Montanarin et al, 2011;Stückler et al, 2019;Fischer et al, 2020), where externally fertilized terrestrial clutches of approximately 20 eggs are laid in the leaf litter (Weygoldt, 1980). Tadpole transport takes place after 15-20 days of larval development and is mainly performed by males (Ringler et al, 2013) but females take over when the male disappears (Ringler et al, 2015b).…”

Contrasting parental roles shape sex differences in poison frog space use but not navigational performance

“…In all three species, males and females show site fidelity, but the levels of aggressiveness and territoriality vary. In A. femoralis and O. sylvatica , males vocally advertise and aggressively defend small territories, while females visit males for mating and show no aggressive behavior (M.-T. Fischer et al, 2020; M. Ringler et al, 2009; Roithmair, 1992; Silverstone, 1973; Summers, 1992; this study). In D. tinctorius , both males and females show intra-sexual aggression as part of territoriality and/or mate guarding, but males do not vocally advertise(Born et al, 2010; Rojas & Pašukonis, 2019; this study).…”

“…The only species with marked sex differences in navigational performance was A. femoralis , where males were more likely to return home, returned from longer distances, and returned faster and more accurately than females. This finding is partially unexpected because A. femoralis females commute between males for reproduction (M.-T. Fischer et al, 2020; E. Ringler et al, 2012) and remember the exact locations of their clutches (E. Ringler et al, 2016). However, because non-homing A. femoralis females typically stay stationary, it is difficult to disentangle the lack of motivation from their inability to return home.…”

“…However, because non-homing A. femoralis females typically stay stationary, it is difficult to disentangle the lack of motivation from their inability to return home. We expected that A. femoralis females would be motivated to return home because they show site fidelity (M.-T. Fischer et al, 2020; M. Ringler et al, 2009; this study) and monitor the presence of their mating partners to eventually take over tadpole transport in case of male absence (E. Ringler, Pašukonis et al, 2015). Indeed, females returned, albeit slower from shorter translocation distances, indicating that they were motivated to return in a sufficiently familiar area.…”

Methods of amphibian tracking

“…На той час метод був передовою технологією, оскільки сам детектор Гейгера-Мюллера розроблено у 1908 р. Тому для середини ХХ ст. це був оптимум для відстежування активності тварин [16]. Метод трекінгу потребував наявності детектора Гейгера-Мюллера, пере давачів, наповнених радіоізотопом, і хірургічних умінь дослідника.…”