Prey profitability is one of the most important factors influencing prey selection. This factor varies along with both prey size and handling time. Thus, large prey are generally highly profitable ...for consumers and boost competition. Kleptoparasitism is a form of competition in which an individual steals food previously obtained by another individual. Accordingly, handling large prey should increase the likelihood of kleptoparasitism occurrence, but these relationships remain poorly understood. Here, we studied kleptoparasitism occurrence by the Brown‐Hooded Gull (Chroicocephalus maculipennis – Laridae) on Whimbrels (Numenius phaeopus hudsonicus – Scolopacidae) preying on intertidal Mole Crabs (Emerita analoga) in a wave‐exposed sandy beach in southern Chile. Generalized linear models, fitted to data from focal‐individual video sequences, showed that kleptoparasitism probability had a positive sigmoidal response to handling time. Moreover, with an increase of 1 s in handling time, a Whimbrel doubled its probability of being kleptoparasitized. Additionally, the odds of being kleptoparasitized were 17% higher with an increase of 10 mm in prey length and 47% higher with an increase of one gull per host. However, the effect of handling on kleptoparasitism probability slightly decreased (2%) with an increase of 10 mm in prey size class. Our results suggest the existence of a threshold time in which consumers can handle their prey before kleptoparasitism probability is too high. Nevertheless, Whimbrel's mean intake rate reached 0.15 ± 0.13 kJ s−1, allowing Whimbrels to theoretically meet their energetic requirements despite losing some prey to kleptoparasites. This study provides new insight into a common form of competition among consumers, highlighting the importance of prey handling time for shorebirds with a restricted foraging time driven by tidal cycles.
Abstract
Parasite–host systems are pervasive in nature but are extremely difficult to convincingly identify in the fossil record. Here we report quantitative evidence of parasitism in the form of a ...unique, enduring life association between tube-dwelling organisms encrusted to densely clustered shells of a monospecific organophosphatic brachiopod assemblage from the lower Cambrian (Stage 4) of South China. Brachiopods with encrusting tubes have decreased biomass (indicating reduced fitness) compared to individuals without tubes. The encrusting tubes orient tightly in vectors matching the laminar feeding currents of the host, suggesting kleptoparasitism. With no convincing parasite–host interactions known from the Ediacaran, this widespread sessile association reveals intimate parasite–host animal systems arose in early Cambrian benthic communities and their emergence may have played a key role in driving the evolutionary and ecological innovations associated with the Cambrian radiation.
In cooperatively breeding species, helpers take higher risks of getting lower return of investment than breeders due to the incongruity between helping and breeding. Helpers can deal with the risk by ...curtailing their investment or, if possible, claiming immediate rewards in the cooperation. Given breeders may rely largely on the aid of helpers to raise their offspring, it can be hypothesized that helpers are more likely to make adaptive responses to the incongruity-associated risk in adverse habitats than in good ones. This hypothesis was tested in the giant babax (
Babax waddelli
) by comparing helpers’ provisioning behaviors between two breeding populations in adverse high-altitude and good low-altitude environments. These two populations differed significantly in their egg size and nestlings’ growth patterns. Helpers in both populations made great contributions to the raising of offspring. During provisioning, helpers in the high-altitude population exhibited significantly higher feeding rates but delivered fewer insects per feeding bout than their counterparts in the low-altitude population. Helpers in both populations displayed a cheating strategy of “non-feeding” to reduce investment in provisioning. They pursued immediate excess rewards via kleptoparasitism of nestling fecal sacs in the high-altitude population but not in the low-altitude one. Accordingly, breeders made different antagonistic actions toward the cheating helpers between populations. Our findings confirm that helpers are prone to deceiving cooperation under poor breeding conditions, and that breeders’ tolerance of the cheating behavior of helpers is determined by their dependence on the helpers’ aid.
Significance statement
Giant babax is an obligated cooperatively breeding bird that breeds on the Tibetan Plateau. We found that helpers displayed cheating behaviors while they provisioned the brood. Although helpers in both high- and low-altitude populations adopt “non-feeding” strategy to reduce investment in the provisioning, they were more likely to perform contested kleptoparasitism to access the fecal sacs of nestling in the high-altitude population than in the low-altitude one. Our findings suggest that helpers in adverse high-altitude habitats are probable to claim immediate excess reward via cheating strategies.
Frugivorous fishes switch their diets seasonally in response to fluctuating food availability; a strategy that maximizes energy and nutrient intake and reduces competition for food. Kleptoparasitism ...is a form of competition that involves the stealing of already‐procured items, for which the host has invested energy in prey capture. We did not find previous studies on kleptoparasitism among Neotropical fish. Here we contribute the first record of kleptoparasitism among a frugivorous fish species. The matrinxã (Brycon falcatus) is a member of an iconic genus of broadly distributed frugivorous fishes. We made focal daylight underwater observations (by snorkeling) of frugivorous fish behavior in an Amazonian stream. Opportunistic feeding interactions between a school of juvenile matrinxã, (B. falcatus) and an individual of threespot leporinus (Leporinus friderici) were observed. The matrinxã stole the fruit that was captured in the substrate by the leporinus. Brycon falcatus usually lives between the middle of the water column to the surface of rivers and streams while Leporinus friderici occupies the lower portion of the water column and it actively forages close to the substrate. This suggests that stealing food from a benthic feeder is an opportunistic ecological interaction to take advantage of scarce resources during the period of food scarcity. This alternative technique of capturing fruits may be advantageous (i.e., save energy expenditures related to searching) for young matrinxã who do not eat fruit as frequently as adults. Our results reflect the trophic plasticity and foraging opportunism characteristic of most tropical freshwater fish. We believe that the hydrological period in which the observations were made, when a few trees were bearing fruit, can favor fruit stealing by Brycon falcatus.
In ecology, foraging requires animals to expend energy in order to obtain resources. The cost of foraging can be reduced through kleptoparasitism, the theft of a resource that another individual has ...expended effort to acquire. Thus, kleptoparasitism is one of the most significant feeding techniques in ecology. The phenomenon of kleptoparasitism has garnered significant attention from scholars due to its substantial impact on the food chain. However, the proportionate amount of mathematical modelling to facilitate the analysis has made limited progress in the literature. This circumstance motivated us to develop mathematical models that could explain the population dynamics of the prey-predator food chain. This study explores a scenario with two predators and one prey, where one predator is a kleptoparasite and the other is a host. The energy depletion caused by the predator's counterattack subsequent to kleptoparasitism, notwithstanding the nonlethal nature of this antagonism, is an additional component incorporated into this model. It has been suggested that biologically viable equilibria must meet certain parametric conditions in order to exist and to be stable both locally and globally. This article delves deeply into the occurrences of various one-parametric bifurcations, such as saddle-node bifurcation, transcritical bifurcation, and Hopf bifurcation, as well as two-parametric bifurcations, such as Bautin bifurcation. A subcritical Hopf bifurcation happens when the growth rate of the first predator is relatively low, while a supercritical Hopf bifurcation occurs when the growth rate of the first predator is quite large, allowing for the coexistence of all three species. Numerical simulations have been conducted to validate our theoretical findings.
Competition typically takes place in a spatial context, but eco-evolutionary models rarely address the joint evolution of movement and competition strategies. Here we investigate a spatially explicit ...forager-kleptoparasite model where consumers can either forage on a heterogeneous resource landscape or steal resource items from conspecifics (kleptoparasitism). We consider three scenarios: (1) foragers without kleptoparasites, (2) consumers specializing as foragers or as kleptoparasites, and (3) consumers that can switch between foraging and kleptoparasitism depending on local conditions. We model movement strategies as individual-specific combinations of preferences for environmental cues, similar to step-selection coefficients. Using mechanistic, individual-based simulations, we study the joint evolution of movement and competition strategies, and we investigate the implications for the distribution of consumers over this landscape. Movement and competition strategies evolve rapidly and consistently across scenarios, with marked differences among scenarios, leading to differences in resource exploitation patterns. In scenario 1, foragers evolve considerable individual variation in movement strategies, while in scenario 2, movement strategies show a swift divergence between foragers and kleptoparasites. In scenario 3, where individuals’ competition strategies are conditional on local cues, movement strategies facilitate kleptoparasitism, and individual consistency in competition strategy also emerges. Even in the absence of kleptoparasitism (scenario 1), the distribution of consumers deviates considerably from predictions of ideal free distribution models because of the intrinsic difficulty of moving effectively on a depleted resource landscape with few reliable cues. Our study emphasizes the advantages of a mechanistic approach when studying competition in a spatial context and suggests how evolutionary modeling can be integrated with current work in animal movement ecology.
The family Spionidae Grube, 1850, one of the most abundant polychaete groups in Annelida in terms of species numbers and biomass, is globally found in a wide variety of marine environments. Among ...this family, members belonging to the Polydora-complex (or referred to as polydorids, Tribe Polydorini, or polydorins) are well known for their ability to bore into various hard calcareous substrates. This group comprises boring and non-boring species, both of which include symbiotic species and therefore utilize a variety of substrates, including other invertebrate species, as habitat. In the course of research on spionid polychaetes in Japan, the author recently discovered and described two new species, Polydora lingulicola Abe & Sato-Okoshi, 2020 and Polydora tunicola Abe, Hoshino & Yamada in Abe, Hoshino, Yamada, Ogino, Kawaida & Sato-Okoshi, 2022, that show novel and unusual obligate symbiotic relationships with lingulid brachiopods and ascidians, respectively. Here I review the known symbiotic relationships in spionid polychaetes, including above two newly discovered symbiotic relationships.
In this study, the behavior of Q. mexicanus was recorded through observations from July to October 2020. The observations period was from 7:00 to 10:00 a.m. and from 2:00 a.m. at 5:00 p.m. Eastern ...Time (ET). During this study we were able to describe 29 specific behaviors that are grouped into nine main functional categories. These categories will be used to construct an ethogram that we hope will be useful to improve our knowledge about the behavior of Q. mexicanus, a bird that practically coexists with humans in the Republic of Panama.
The interspecific interactions of apex predators are integral to the function of ecological communities, but most studies have focused on understanding their top down effects. Kleptoparasitism (the ...stealing of procured food) by dominant scavengers can have negative effects on populations and behaviors of apex predators. We captured 7 pumas (Puma concolor) and fitted them with GPS collars to investigate potential kill sites (n = 352), some of which we monitored with camera traps (n = 58). We analyzed whether observed kleptoparasitism by American black bears (Ursus americanus) affected puma energetics and foraging behavior. We found that black bears were the most frequent scavenger of puma kills (72.4%), and we documented bears scavenging puma kills during every month. The top model for bear detection of puma kills included prey size, temperature, and canopy cover, with bears more likely to scavenge from adult black-tailed deer (Odocoileus hemionus columbianus) carcasses in warmer temperatures and under dense canopy cover. When black bear scavenging occurred, pumas spent 22% less time at their kill and incurred energetic losses. In response, pumas shortened their inter-kill intervals by 1.3 days thus increasing their kill rates. Our results demonstrate how a dominant scavenger directly mediates the foraging behavior of an apex predator. These results suggest that community interactions do not necessarily start at the top in top-down systems, and the effects of predators on prey populations can only be understood within their respective ecological communities.
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