The Role of Red Leaf Coloration in Prey Capture forPinguicula planifolia

How task specialization, individual task performance and within-group behavioural variation affects fitness is a longstanding and unresolved problem in our understanding of animal societies. In the temperate social spider, Anelosimus studiosus , colony members exhibit a behavioural polymorphism; females either exhibit an aggressive ‘asocial’ or docile ‘social’ phenotype. We assessed individual prey-capture success for both phenotypes, and the role of phenotypic composition on group-level prey-capture success for three prey size classes. We then estimated the effect of group phenotypic composition on fitness in a common garden, as inferred from individual egg-case masses. On average, asocial females were more successful than social females at capturing large prey, and colony-level prey-capture success was positively associated with the frequency of the asocial phenotype. Asocial colony members were also more likely to engage in prey-capture behaviour in group-foraging situations. Interestingly, our fitness estimates indicate females of both phenotypes experience increased fitness when occupying colonies containing unlike individuals. These results imply a reciprocal fitness benefit of within-colony behavioural variation, and perhaps division of labour in a spider society.

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Distance and Size Discrimination in a Water Stick Insect, ranatra linearis (Heteroptera)

Journal of Experimental Biology ◽

10.1242/jeb.120.1.59 ◽

1986 ◽

Vol 120 (1) ◽

pp. 59-77

Author(s):

ANN CLOAREC

Keyword(s):

Prey Capture ◽

Stick Insect ◽

Normal Adult ◽

Central Position ◽

Size Discrimination ◽

Stick Insects ◽

Distance Position ◽

Prey Items

The role of vision in distance, position and size discrimination in prey capture has been investigated in normal adult water stick insects (Ranatra linearis L.: Heteroptera) and in ones with one eye covered. Both monocular and intact Ranatra were able to discriminate between two targets subtending the same angle but presented at different distances. They usually chose the target nearer to their foreleg claws. Although monocular subjects undershot more often than controls, they could still estimate distance correctly. When presented with two different-sized targets at the same distance, both monocular and intact subjects usually preferred the larger target within a 1°-10° range, even though monocular animals chose the larger object less consistently. They were able to distinguish between two targets differing in size by only 1°. Asymmetrical presentations of two identical targets stressed the importance of the central position. Intact animals always preferred the target nearer their midline. These data also revealed the unexpected ability of Ranatra to strike accurately at two targets or prey items simultaneously. When two identical targets were presented simultaneously and symmetrically, aims were directed at both targets, and one was grasped by each raptorial foreleg, thus indicating an absence of confusion.

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Translation of N.B.K. Sänger’s (1871) “Peripatus capensis Gr. and Peripatus leuckartii n. sp.” (Onychophora), along with remarks about the author and significance of his work

Australian Zoologist ◽

10.7882/az.2021.022 ◽

2021 ◽

Author(s):

Noel N. Tait ◽

Ivo de Sena Oliveira ◽

Georg Mayer

Keyword(s):

Prey Capture ◽

Zoological Institute ◽

Genital Opening ◽

Specific Location ◽

The Central Nervous System ◽

Basic Biology ◽

Giant Fibres ◽

The 19Th Century ◽

Excretory Organs

ABSTRACT The basic biology of onychophorans was revealed slowly and controversially during much of the 19th century. Communications were in Latin, French, Spanish, German and English. This information was synthesised in the monumental monographs of Bouvier in 1905 and 1907. However, amongst this multicultural endeavour is a significant Russian contribution by Nikolai Sänger, a student of Professor Leuckart of the Zoological Institute in Leipzig, Germany. Sänger requested a specimen of Onychophora from the Institute’s collection for serial sectioning. This resulted in a detailed account of the anatomy of Peripatopsis capensis. Sänger’s description of the extensive slime glands was the first to recognise them as the hallmark of onychophorans for defence and prey capture, and not the male reproductive system as previously claimed. Based on these morphological observations, he correctly concluded that onychophorans are not hermaphrodites and, furthermore, are “predominantly predaceous” animals. He further appropriately assigned the slime glands and salivary glands to the slime papilla segment, despite the lack of embryological data at that time. Sänger also identified the excretory organs (nephridia) and their openings, although he erroneously assigned them to a dual role of excretion and respiration. Moreover, he highlighted the importance of the position of the genital opening as a diagnostic character, described the ventral/preventral organs as “subcutaneous glandules”, identified the neurilemma enclosing the central nervous system, and recognised “oval holes of different sizes” in each nerve cord that were subsequently demonstrated to represent giant fibres. Of interest to parasitologists, he discovered a larval acanthocephalan encysted within the cutaneous muscles of his specimen of P. capensis, suggesting that onychophorans act as a secondary host for this parasite. Sänger’s memoir concludes with a brief but important description of the first species of Onychophora recorded from Australia, “northwest of Sydney, New Holland”. This species is now known as Euperipatoides leuckartii with a neotype designated from a specific location northwest of Sydney.

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A novel intramandibular joint facilitates feeding versatility in the sixbar distichodus

Journal of Experimental Biology ◽

10.1242/jeb.243621 ◽

2022 ◽

Author(s):

Christopher M. Martinez ◽

Angelly J. Tovar ◽

Peter C. Wainwright

Keyword(s):

Prey Capture ◽

Teleost Fishes ◽

Feeding Mode ◽

Substrate Interaction ◽

Lower Jaw ◽

Single Structure ◽

Jaw Protrusion ◽

Benthic Prey ◽

Analysis Of Motion

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.

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Neuroendocrine modulation of predator avoidance/prey capture tradeoffs: Role of tectal NPY2R receptors

General and Comparative Endocrinology ◽

10.1016/j.ygcen.2019.113214 ◽

2019 ◽

Vol 282 ◽

pp. 113214 ◽

Cited By ~ 2

Author(s):

Ranakul Islam ◽

Christine M. Prater ◽

Breanna N. Harris ◽

James A. Carr

Keyword(s):

Predator Avoidance ◽

Prey Capture

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The functional roles of passive electroreception in non-electric fishes

Animal Biology ◽

10.1163/157075604323010024 ◽

2004 ◽

Vol 54 (1) ◽

pp. 1-25 ◽

Cited By ~ 62

Author(s):

Darryl Whitehead ◽

Shaun Collin

Keyword(s):

Prey Capture ◽

Large Range ◽

Sensory System ◽

Functional Roles ◽

Carcharhinus Leucas ◽

Aquatic Vertebrates ◽

Bull Shark ◽

Electric Fishes

AbstractPassive electroreception is a complex and specialised sense found in a large range of aquatic vertebrates primarily designed for the detection of weak bioelectric fields. Particular attention has traditionally focused on cartilaginous fishes, but a range of teleost and non-teleost fishes from a diversity of habitats have also been examined. As more species are investigated, it has become apparent that the role of electroreception in fishes is not restricted to locating prey, but is utilised in other complex behaviours. This paper presents the various functional roles of passive electroreception in non-electric fishes, by reviewing much of the recent research on the detection of prey in the context of differences in species' habitat (shallow water, deep-sea, freshwater and saltwater). A special case study on the distribution and neural groupings of ampullary organs in the omnihaline bull shark, Carcharhinus leucas, is also presented and reveals that prey-capture, rather than navigation, may be an important determinant of pore distribution. The discrimination between potential predators and conspecifics and the role of bioelectric stimuli in social behaviour is discussed, as is the ability to migrate over short or long distances in order to locate environmentally favourable conditions. The various theories proposed regarding the importance and mediation of geomagnetic orientation by either an electroreceptive and/or a magnetite-based sensory system receives particular attention. The importance of electroreception to many species is emphasised by highlighting what still remains to be investigated, especially with respect to the physical, biochemical and neural properties of the ampullary organs and the signals that give rise to the large range of observed behaviours.

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