Biology subjects

Herberstein, M. E.

Publications and source records attributed to Herberstein, M. E..

4 recordsLinked to original sources

bioRxiv2025

Context-dependent abdomen bobbing in a jumping spider: a dynamic visual signal

Anti-predatory visual signals play a key role in deterring predatory attacks, and can include crypsis, warning colors or visual mimicry. Static traits such as shape or color are well-studied, whereas locomotion-related signals remain less understood despite being particularly intriguing as they can be controlled by the animals perception of danger. In this study, we explore the potential function of a highly conspicuous dynamic behavior--abdomen bobbing--exhibited by the diurnal jumping spider Heliophanus cf. cupreus during locomotion. Due to the high conspicuousness, we hypothesized that abdomen bobbing could function as a visual signal, specifically as an anti-predatory signal. To test this hypothesis, we first analyzed the behavior and found that bobs occur almost exclusively during gait stops (98.5%) with 83.5% of gait stops entailing abdomen bobbing. We then examined its context-dependency, measuring the prevalence of abdomen bobbing under four conditions: 1) control, 2) in darkness, 3) during prey encounters, 4) during simulated conspecific encounters (i.e. mirror), and 5) during predator encounters. Abdomen bobbing was virtually absent in darkness and during prey encounters, but significantly increased during conspecific and predator encounters, suggesting active control. The increase in abdomen bobbing when confronted with a predator strongly supports an anti-predatory signaling function, potentially a form of locomotion mimicry. We equally found support for an intra-specific signaling function, which might indicate the co-option of a signal from one context (predatory) to another (conspecific). Our study opens new avenues for investigating the role of motion in both inter- and intraspecific signaling.

animal behavior and cognition↗

bioRxiv2023

A state with increased arousal threshold in Araneus diadematus (Araneidae) measured in the wild: new evidence for sleep in spiders

Sleep is a seemingly universal behavior across the animal kingdom, yet for the majority of species, experimental evidence thereof is still lacking. The recent report of REM sleep-like behavior in a jumping spider has highlighted the potential of spiders as a non-model organism to study invertebrate sleep. While behavioral evidence of potential sleep-states in spiders is strong, a crucial piece of evidence is so far lacking: a shift in arousability during sleep compared to awake states. Targeting a spider exquisitely suited for conducting experiments in the wild, we collected arousal threshold data for the diurnal orb-web spider Araneus diadematus. Our field experiments revealed significant differences in response latency between day- and night-times. Using a sound stimulus of 400 Hz with increasing amplitude that robustly triggers an anti-predatory response (raising of front legs), we tested both immobile and active spiders during the day and during the night. We found that spiders had a significantly longer response latency to the stimulus during nighttime immobility compared to immobile spiders during the day. There was no difference in the response latency between active spiders at night and active spiders during the day. Overall, our data demonstrate a shift in arousability during periods of night-time immobility in support of sleep in A. diadematus. Additionally, however, we found eight spiders that did not respond to the stimulus within the set time limit, most of which we encountered during daytime immobility hinting at additional sleep behavior during the day and a potential bimodal sleep pattern. Our study, along with recent work on jumping spider sleep-like behavior showcases the suitability of spiders for sleep research.

animal behavior and cognition↗

bioRxiv2021

Sexual and developmental variations of ecto-parasitism in damselflies

The prevalence and intensity of parasitism can have different fitness costs between sexes, and across species and developmental stages. This variation could arise because of species specific sexual and developmental differences in body condition, immunity, and resistance. Theory predicts that the prevalence of parasitism will be greater in individuals with poor body condition and the intensity of parasitism will be greater in individuals with larger body size. These predictions have been tested and verified in vertebrates. In insects, however, contradictory evidence has been found in different taxa. Here, we tested these predictions on two species of Agriocnemis (Agriocnemis femina and Agriocnemis pygmaea) damselflies, which are parasitized by Arrenurus water mite ectoparasites. We measured body weight, total body length, abdomen area and thorax area of non-parasitized damselflies and found body condition varied between males and females, between immature females and mature females and between A. femina and A. pygmaea. Then, we calculated the parasite prevalence, i.e., the frequency of parasitism and intensity, i.e., the number of parasites per infected damselfly in eleven natural populations of both species. In line to our predictions, we observed greater prevalence in immature females than mature females but found no difference in parasite prevalence between males and females. Furthermore, we found that parasite load was higher in females than males and in immature females than mature females. Our result also showed that the frequency and intensity of parasitism varied between the two studied species, being higher in A. pygmaea than A. femina. Our study provides evidence that parasitism impacts sexes, developmental stages and species differentially and suggests that variation may occur due to sex, developmental stage, and species-specific resistance and tolerance mechanism.

evolutionary biology↗

bioRxiv2020

Male-male interactions select for conspicuous male colouration in damselflies

Male ornamentation, such as conspicuous male colouration, can evolve through female mate choice. Alternatively, in species without overt female mate preference, conspicuous male colouration can evolve via intrasexual selection to resolve male-male competition or to prevent costly male-male mating attempts. Here, we investigated the drivers of conspicuous male colouration in an ontogenetic colour changing damselfly, Xanthagrion erythroneurum, where the juvenile males are yellow and change colour to red upon sexual maturity. We first showed that red males were chromatically and achromatically more conspicuous than the yellow males. We then quantified the condition of the males and showed that red males were larger and in better condition than yellow males. We tested female preference in a choice experiment where we artificially manipulated male colour, and found that females did not choose mates based on male colouration. We further tested whether the male colouration affected male-male interactions. We presented red and yellow males in the breeding arena, and found that red males received less intra- and interspecific aggression than yellow males. Our study experimentally showed, for the first time, that male conspicuousness is not a target of female mate choice in damselflies. Intra- and interspecific male-male interactions therefore appear to be the driver of conspicuous male colouration in damselflies.View Full Text

animal behavior and cognition↗