scholarly journals Kleptopredation: a mechanism to facilitate planktivory in a benthic mollusc

2017 ◽  
Vol 13 (11) ◽  
pp. 20170447 ◽  
Author(s):  
Trevor J. Willis ◽  
Kimberly T. L. Berglöf ◽  
Rona A. R. McGill ◽  
Luigi Musco ◽  
Stefano Piraino ◽  
...  

Predation occurs when an organism completely or partially consumes its prey. Partial consumption is typical of herbivores but is also common in some marine microbenthic carnivores that feed on colonial organisms. Associations between nudibranch molluscs and colonial hydroids have long been assumed to be simple predator–prey relationships. Here we show that while the aeolid nudibranch Cratena peregrina does prey directly on the hydranths of Eudendrium racemosum , it is stimulated to feed when hydranths have captured and are handling prey, thus ingesting recently captured plankton along with the hydroid polyp such that plankton form at least half of the nudibranch diet. The nudibranch is thus largely planktivorous, facilitated by use of the hydroid for prey capture. At the scale of the colony this combines predation with kleptoparasitism, a type of competition that involves the theft of already-procured items to form a feeding mode that does not fit into existing classifications, which we term kleptopredation. This strategy of subsidized predation helps explain how obligate-feeding nudibranchs obtain sufficient energy for reproduction from an ephemeral food source.

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
J L Ward ◽  
V Korn ◽  
A N Auxier ◽  
H L Schoenfuss

Synopsis A variety of environmental estrogens are commonly detected in human-impacted waterways. Although much is known about the effects of these environmental estrogens on the reproductive physiology and behavior of individuals within species, comparatively less is known about how these compounds alter the outcomes of interactions between species. Furthermore, few studies have considered how the effects of contaminants are modulated by natural variation in abiotic factors, such as temperature. To help fill this knowledge gap, we conducted a factorial experiment to examine the independent and combined effects of estrone (E1) and temperature on the outcome of predator–prey interactions between two common North American freshwater fishes, fathead minnows (Pimephales promelas) and bluegill sunfish (Lepomis macrochirus). Larval fathead minnows and adult sunfish were exposed to either a low (mean±standard deviation, 90.1 ± 18 ng/L; n = 16) or high (414 ± 147 ng/L; n = 15) concentration of E1 or to a solvent control for 30 days at one of four natural seasonal temperatures (15°C, 18°C, 21°C, and 24°C) before predation trials were performed. Exposure to E1 was associated with a significant increase in larval predation mortality that was independent of temperature. Across all temperature treatments, approximately 74% of control minnows survived; this survivorship significantly exceeded that of minnows exposed to either concentration of E1 (49% and 53% for minnows exposed to the low and high concentrations, respectively). However, exposure to E1 also impaired the prey-capture success of sunfish, partially mitigating predation pressure on exposed minnows. Overall prey-capture success by sunfish showed an inverted U-shaped distribution with temperature, with maximal prey consumption occurring at 21°C. This study illustrates the vulnerability of organismal interactions to estrogenic pollutants and highlights the need to include food web interactions in assessments of risk.


2014 ◽  
Vol 281 (1790) ◽  
pp. 20141083 ◽  
Author(s):  
Jérôme Casas ◽  
Thomas Steinmann

Many prey species, from soil arthropods to fish, perceive the approach of predators, allowing them to escape just in time. Thus, prey capture is as important to predators as prey finding. We extend an existing framework for understanding the conjoint trajectories of predator and prey after encounters, by estimating the ratio of predator attack and prey danger perception distances, and apply it to wolf spiders attacking wood crickets. Disturbances to air flow upstream from running spiders, which are sensed by crickets, were assessed by computational fluid dynamics with the finite-elements method for a much simplified spider model: body size, speed and ground effect were all required to obtain a faithful representation of the aerodynamic signature of the spider, with the legs making only a minor contribution. The relationship between attack speed and the maximal distance at which the cricket can perceive the danger is parabolic; it splits the space defined by these two variables into regions differing in their values for this ratio. For this biological interaction, the ratio is no greater than one, implying immediate perception of the danger, from the onset of attack. Particular attention should be paid to the ecomechanical aspects of interactions with such small ratio, because of the high degree of bidirectional coupling of the behaviour of the two protagonists. This conclusion applies to several other predator–prey systems with sensory ecologies based on flow sensing, in air and water.


2001 ◽  
Vol 79 (10) ◽  
pp. 1834-1841 ◽  
Author(s):  
Michael T Anderson ◽  
Joseph M Kiesecker ◽  
Douglas P Chivers ◽  
Andrew R Blaustein

Abiotic factors may directly influence community structure by influencing biotic interactions. In aquatic systems, where gape-limited predators are common, abiotic factors that influence organisms' growth rates potentially mediate predator–prey interactions indirectly through effects on prey size. We tested the hypothesis that temperature influences interactions between aquatic size-limited insect predators (Notonecta kirbyi) and their larval anuran prey (Hyla regilla) beyond its indirect effect on prey size. Notonecta kirbyi and H. regilla were raised and tested in predator–prey trials at one of three experimentally maintained temperatures, 9.9, 20.7, or 25.7°C. Temperature strongly influenced anuran growth and predator success; mean tadpole mass over time was positively related to temperature, while the number of prey caught was negatively related. At higher temperatures tadpoles attained greater mass more quickly, allowing them to avoid capture by notonectids. However, the probability of capture is a function of both mass and temperature; temperature was a significant explanatory variable in a logistic regression equation predicting prey capture. For a given prey mass, tadpoles raised in warmer water experienced a higher probability of capture by notonectids. Thus, rather than being static, prey size refugia are influenced directly by abiotic factors, in this case temperature. This suggests that temperature exerts differential effects on notonectid and larval anurans, leading to differences in the probability of prey capture for a given prey mass. Therefore, temperature can influence predator–prey interactions via indirect effects on prey size and direct effects on prey.


2016 ◽  
Vol 283 (1838) ◽  
pp. 20161294 ◽  
Author(s):  
Timothy E. Higham ◽  
Sean M. Rogers ◽  
R. Brian Langerhans ◽  
Heather A. Jamniczky ◽  
George V. Lauder ◽  
...  

Speciation is a multifaceted process that involves numerous aspects of the biological sciences and occurs for multiple reasons. Ecology plays a major role, including both abiotic and biotic factors. Whether populations experience similar or divergent ecological environments, they often adapt to local conditions through divergence in biomechanical traits. We investigate the role of biomechanics in speciation using fish predator–prey interactions, a primary driver of fitness for both predators and prey. We highlight specific groups of fishes, or specific species, that have been particularly valuable for understanding these dynamic interactions and offer the best opportunities for future studies that link genetic architecture to biomechanics and reproductive isolation (RI). In addition to emphasizing the key biomechanical techniques that will be instrumental, we also propose that the movement towards linking biomechanics and speciation will include (i) establishing the genetic basis of biomechanical traits, (ii) testing whether similar and divergent selection lead to biomechanical divergence, and (iii) testing whether/how biomechanical traits affect RI. Future investigations that examine speciation through the lens of biomechanics will propel our understanding of this key process.


Author(s):  
Christopher M. Martinez ◽  
Angelly J. Tovar ◽  
Peter C. Wainwright

The intramandibular joint (IMJ) is a secondary point of movement between the two major bones of the lower jaw. It has independently evolved in several groups of teleost fishes, each time representing a departure from related species in which the mandible functions as a single structure rotating only at the quadratomandibular joint (QMJ). In this study, we examine kinematic consequences of the IMJ novelty in a freshwater characiform fish, the herbivorous Distichodus sexfasciatus. We combine traditional kinematic approaches with trajectory-based analysis of motion shapes to compare patterns of prey capture movements during substrate biting, the fish's native feeding mode, and suction of prey from the water column. We find that the IMJ enables complex jaw motions and contributes to feeding versatility by allowing the fish to modulate its kinematics in response to different prey and to various scenarios of jaw-substrate interaction. Implications of the IMJ include context-dependent movements of lower versus upper jaws, enhanced lower jaw protrusion, and the ability to maintain contact between the teeth and substrate throughout the jaw closing or biting phase of the motion. The IMJ in D. sexfasciatus appears to be an adaptation for removing attached benthic prey, consistent with its function in other groups that have evolved the joint. This study builds on our understanding of the role of the IMJ during prey capture and provides insights into broader implications of the innovative trait.


2007 ◽  
Vol 121 (2) ◽  
pp. 216 ◽  
Author(s):  
E. Natasha Vanderhoff

I observed a predator-prey interaction between a juvenile American Robin (Turdus migratorius L.) and a juvenile Five-lined Skink (Eumeces fasciatus L.). Although Robins are considered omnivorous, there are no previous reports of a robin eating lizards although they have been recorded as occasionally taking snakes. I discuss the age of the individuals involved as it relates to prey capture and escape.


1997 ◽  
Vol 200 (15) ◽  
pp. 2145-2154 ◽  
Author(s):  
D Nemeth

Changes in intraoral pressure during prey capture were recorded for a trophic generalist, Hexagrammos decagrammus, feeding on different prey species. Prey were grouped into elusive (shrimps), grasping (isopods and crabs) and non-elusive (pieces of shrimp) categories. Elusive and grasping prey elicited strikes with a larger and faster reduction in buccal pressure than did non-elusive prey. The suction force generated by the predator differed for strikes among the shrimp genera in the elusive prey category. The most sedentary shrimps (Crangon alaskensis and C. nigricauda) elicited the fastest and greatest reduction in pressure relative to the most evasive shrimps (Pandalus danae and Heptacarpus stylus). A preparatory phase, during which the buccal cavity is compressed prior to the strike, occurred significantly more frequently in strikes at grasping prey than in strikes at elusive and non-elusive prey, and more frequently for elusive than for non-elusive prey. Prey size did not influence the suction force generated by the predator. No differences in buccal pressure patterns were detected between strikes that resulted in a capture or a miss, suggesting that misses were due to the escape behavior of the prey and were not the result of an inappropriate suction force. These data support the current view that fish can modify their feeding mode in response to prey behavior, and they emphasize that the behavioral responses of the individual prey must be considered when defining the appropriate strategy for prey capture. The use of a flexible, modifiable feeding behavior is associated with a broad diet in H. decagrammus and may increase capture success on diverse prey relative to that of other species showing stereotypical feeding responses.


2002 ◽  
Vol 205 (7) ◽  
pp. 999-1007 ◽  
Author(s):  
Brandon R. Brown

SUMMARYMost biological sensory systems benefit from multiple sensors. Elasmobranchs (sharks, skates and rays) possess an array of electroreceptive organs that facilitate prey location, mate location and navigation. Here, the perceived electrosensory landscape for an elasmobranch approaching prey is mathematically modeled. The voltages that develop simultaneously in dozens of separate sensing organs are calculated using electrodynamics. These voltages lead directly to firing rate modifications in the primary afferent nerves. The canals connecting the sense organs to an elasmobranch's surface exhibit great variation of location and orientation. Here, the voltages arising in the sense organs are found to depend strongly on the geometrical distribution of the corresponding canals. Two applications for the modeling technique are explored: an analysis of observed elasmobranch prey-capture behavior and an analysis of morphological optimization. For the former, results in specific predator-prey scenarios are compared with behavioral observations, supporting the approach algorithm suggested by A. Kalmijn. For the latter, electrosensory performance is contrasted for two geometrical models of multiple sense organs,a rounded head and a hammer-shaped head.


Pramana ◽  
2020 ◽  
Vol 94 (1) ◽  
Author(s):  
M Krishnadas ◽  
P P Saratchandran ◽  
K P Harikrishnan

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