Ethology最新文献

The European cave spider (Meta menardi) builds orb webs in the entrance and twilight zone of caves. However, the scarcity of flying prey inside caves means that only about half of its diet consists of flying insects, with walking prey making up the remaining half. The capture of non-flying prey is not generally known from aboveground orb web building spiders, which exclusively capture flying prey in their webs. It is currently a mystery how the cave spider manages to capture prey walking on the cave wall. A number of hypotheses have been suggested, including that the spider leaves its web completely (the off-web hunting hypothesis), that walking prey slips on the smooth cave ceiling and falls into the horizontally inclined webs (the prey slip hypothesis) or that the unique geometry of the cave spider's orb web, which lacks frame threads, means that the radii that attach directly to the cave wall are used as tripwires to alert the spider of passing prey (the radius tripwire hypothesis). Here we report on three in situ observations of M. menardi responding to radius stimulation from artificial and walking prey by running towards the cave wall. Although the opportunistic observations of responses to real prey both involved potentially dangerous prey (a centipede and another large M. menardi) and were unsuccessful prey capture events, the clear response to walking prey nonetheless constitutes the first strong observational evidence in support of the radius tripwire hypothesis.

“Damn, they didn't cite me!” Do you know this feeling? Honestly, I have experienced such a wave of anger and disappointment quite often when reading papers close to my field. In some cases, I felt so wronged that I sent a friendly email to the authors reminding them of my work. Maybe they just did not know about it? Maybe they did a poor job of searching for the relevant literature? Or they thought my work was not of sufficient quality to be cited? Or is it that I keep choosing the wrong keywords so that no one can find my studies? I am sure, others will have thought the same about some of my papers, that is I did not cite their work even though it was relevant.

There are many reasons why relevant publications are not cited. In the worst case, it can be scientific misconduct, that is authors deliberately fail to cite other people's work when they know it is relevant and should be cited. I am convinced, however, that this is only a minority of cases. In recent decades, the number of scientific studies (and journals) has kind of exploded, making it difficult to keep up with developments even within one's own field. Combined with a poor literature search, this can lead to the omission of relevant work. Further, instead of searching for relevant literature themselves, many people rely on reviews, but this means that the quality of the respective review determines whether readers find the relevant literature to cite. Plus, there may be a good number of other reasons why studies are not cited, but I want to focus on one important cause that is in the responsibility of publishers.

Many journals, especially such with a high impact, have word limits for their articles. In principle, this is fine, as it forces authors to write in a concise and focused manner. However, the word limit often includes the references. In my view, this is plain wrong and should never happen. When the word limit includes references, it is of course much easier for authors to shorten their articles simply by omitting references rather than by reducing their text: eliminating 10 or so references can easily save 150 and more words. In other cases, journals do not include citations in their word limit, but instead they limit the allowed number of references as such. This basically means that the journal forces authors to actively exclude potentially relevant references. In the worst case, such a reference limit is even requested for review articles, whose main purpose should be to provide an overview by including ideally all of the relevant citations.

Sometimes, the authors of articles that did not cite my work responded to my emails. In a few cases, they stated that they were not aware of my work and were grateful that I had brought it to their attention. In most cases, however, they said that they had to focus on the most relevant citations because of word limits or restrictions on the number of citations allowed. And of course, they and I may disagree about wh

Most Parid species produce specific, order-constrained mobbing calls. These calls elicit responses from both conspecifics and heterospecifics, with evidence indicating that such responses occur only when the calls are organised in this specific order. One notable exception is the coal tit (Periparus ater), a species that employs similar types of notes, yet does not exhibit clear order constraints within its mobbing sequences. Despite this apparent absence of order constraints, a recent experiment has demonstrated that coal tits may be sensitive to the order of notes in heterospecific calls. Therefore, the relative significance of note order in conspecific and heterospecific communication among coal tits remains unclear. We conducted a playback experiment to examine the effects of note order (natural coal tit order, typical Parid order and reversed order) and species identity (conspecific, familiar heterospecific—the great tit, Parus major, or artificial notes) on coal tit mobbing responses. Our findings indicate that coal tits exhibited a strong response to conspecific calls, regardless of the order of the notes; conversely, they displayed little to no response to heterospecific calls and artificial notes, irrespective of note order. A similar pattern was observed when assessing the general community response. This unexpectedly low response to familiar heterospecific calls may be attributable to a reduced density of great tits in the area we tested: ecological factors, such as community composition, may influence heterospecific mobbing behaviours and the subsequent biological interpretations of playback experiments. This study also underscores the necessity of conducting comparative research on closely related species to evaluate the potential generality of findings, such as strong order constraints recently observed in great tits and Japanese tits.

Spider silk is a versatile material that is exploited by its creators, but potentially also by other animals once deposited into the environment. In this study, we report on gall midges from the family Cecidomyiidae in Australia exploiting spider silk as roosting sites. Across two distant locations in New South Wales, Australia, we observed adult midges suspended motionless on aerial lines by their front pair of legs yet able to liberate themselves when disturbed. The benefit of using silk as a resting surface may include a reduction in predation risk by terrestrial and aerial predators that cannot reach individuals suspended in the air. This does not appear to be associated with an increased risk of predation by the silk-owners, given that the silk exploited for roosting is not part of aerial webs or capture threads that are sticky. Our observations complement those of gall midges from other continents that show an invertebrate actively exploiting the extended phenotype of a spider, which is an unexpected relationship between these animal types where one is typically the prey of the other. The capacity to suspend on silk lines may require certain silk line orientations or web architectures, constraining midges to exploit the extended phenotype of specific types of spiders.

Animal behavior research has significantly advanced our understanding of animals as sentient, behaviorally complex, and often highly social beings. It has also deepened our knowledge of their needs and laid important foundations for how to treat them and their environments ethically and respectfully. It is paradoxical that bureaucratic hurdles and a political push to replace or drastically reduce animal experimentation now increasingly impede this research field. A group of established researchers working in the field of animal behavior covering topics from animal welfare, the consequences of individuality, chemical communication, and behavioral development has now highlighted the urgent need for a more nuanced perspective on animal experiments (Richter et al. 2025).

The debate between proponents, emphasizing the necessity of animal experiments in research, and opponents, raising animal welfare concerns, has led to entrenched positions and a polarized, black-and-white view of the issue. Close to 8 million animals are used in approved experiments across the European Union every year—comprising the ~7.5% being used in animal behavior studies, but also in a wide range of fields, from cancer research to drug testing and more. Here, at the latest, it should become obvious that animal experiments do not fit in just one drawer. They range from simply observing a fish swimming in a tank (a procedure with no burden to the animal) to attaching a small geolocator on a stork to understand its migration route, to conducting highly invasive procedures, for example, in testing cancer drugs or testing the safety of chemicals. While the severity (a measure to estimate the burden to the animals) of these examples greatly differs, all experiments are subject to the same rigorous and extensive ethical approval process. However, the vast majority of animal behavior and welfare studies impose at most only mild stress (the lowest of the severity classes) on the experimental animals. The authors therefore propose that the European severity classification of experimental procedures (Mild, Moderate, Non-recovery, and Severe) should also inform the permitting process, suggesting that lower severity levels correspond to expedited approvals (Richter et al. 2025). Our focus, like that of Richter et al. (2025), is solely on the European situation. However, expanding the discussion to include regulations and procedures in other countries and continents could provide valuable insights.

Placing behavioral research in one category with more intrusive investigations, and the rigorous permitting procedures attached to it, causes serious problems in the field of education: School teachers find it almost impossible to introduce their pupils to live animals and it becomes increasingly difficult—even at the university level—to teach the correct handling of animals to zoology students and to induce a healthy empathy with animals. This

For animals that traverse patchy or dynamic backgrounds, morphological color change can help to stay hidden from predators and prey. The green lynx spider (Peucetia viridans) is a sit-and-wait predator that hunts pollinators and other insects among vegetation. In the field, it is often bright green with variable patterns of white, red, orange, yellow, and purple, and individuals often appear well-matched to their backgrounds. A previous study that relied on human observers to assess color suggested these spiders can shift their body colors to match their surroundings. Our goal was to replicate this work using modern reflectance spectrophotometry to quantify spider colors. Across two experiments (in different years), we collected adult female spiders and assigned them to three differently colored backgrounds in the lab. Unexpectedly, we found little evidence that the spiders in our study shifted their colors to match their backgrounds. However, exploratory analyses revealed that color change did occur, just not as expected, and was likely related to senescence, diet, body condition, or some combination. We discuss these findings in the context of previous work and suggest that the complex nature of color change in this species makes it a promising candidate to provide novel insights for the field.

Animals across taxa form aggregations, with increased defenses as one of the benefits. Some defensive behaviors of grouped animals involve body movements. However, how those behaviors are triggered varies, and how between-individual morphological variation affects them remains unknown. In this project, we explored three drivers of bobbing—an up-and-down body vibration behavior assumed to be a defensive response—with field observations and a lab experiment in one species of the arachnid order Opiliones (Prionostemma sp.2). First, we explored the variation in bobbing duration across groups of a variable number of individuals, as animals could modulate their engagement in this behavior to ensure a successful predator-deterrent behavior. We found that the duration of bobbing increased with group size. Second, we explored the effect of different triggering stimuli that might represent natural scenarios of an approaching predator. We found that a touching stimulus (gentle stick touching) triggered longer bobbing than an airflow stimulus (gentle blow). Third, we explored if the individuals' leg condition (whether they had all eight or fewer legs when found) affects their engagement in this behavior. We found that variations in leg condition did not affect their defensive engagement, as bobbing duration was similar between intact individuals and those missing legs. Together, these data provide novel observational and experimental insights into the drivers of collective behavior in animals. While individual variation in morphological conditions does not affect bobbing in these understudied arachnids, variability in group size and the triggering stimuli impacted their engagement in movement behavioral defenses.

Sometimes we should take a closer look at the natural behaviour of even the most familiar domestic mammals. An example is the nesting behaviour of the female European rabbit Oryctolagus cuniculus and her offspring. After giving birth in a nest of dry grass and fur, mothers return to briefly nurse once a day and deposit faecal pellets there. In domestic rabbits, we examined the temporal pattern of mothers' defecation in the nest, the response of pups to these faeces and the effect of these and nest hay on pups' pre- and postweaning growth and survival. In Experiment 1, we tested primiparous and multiparous mothers given a nest box and hay and allowed access to their pups once a day to nurse. We recorded daily the number of faecal pellets deposited in the nest and the number nibbled by the pups until weaning on postnatal day 30. Mothers defecated in the nest until around postnatal day 12. The pellets and hay then started to be nibbled by the pups, and histological analysis showed that pups ingested plant material. We found no difference in maternal behaviour between primiparous and multiparous females. In Experiment 2, we investigated the growth and survival of pups before and after weaning: (1) with hay and mother's faeces present in the nest; (2) without hay; (3) without mother's faeces; and (4) without hay or mother's faeces. In condition 1, pups transitioned to solid food with little sign of digestive pathology, whereas in conditions 2 and 3, and particularly in condition 4, pups developed diarrhoea and several died. Thus, the presence of nest hay and mother's faeces appear to contribute to pups' transition to solid food. We conclude that rabbits show a well-coordinated pattern of behaviour between mothers and their preweaning offspring, likely relevant to the appropriate management of domestic rabbits.