Raptorial Legs Research Articles

Patterns of morphological evolution in the raptorial appendages of praying mantises.

Mantodea (praying mantises) is a group of exclusively predatory insects, which, together with nonraptorial blattodeans (cockroaches and termites) and groups exclusively found in the fossil record, form the group Dictyoptera. A central characteristic of Mantodea is the specialization of their first pair of legs as raptorial grasping appendages, but the evolution from walking to raptorial legs is not yet fully understood. Here, we trace the evolution of the raptorial appendages in Dictyoptera through time using a morphometric (morphospaces) approach. We also describe two new mantodean nymphs preserved in amber from the Cretaceous and Eocene, which expand the scarce mantodean fossil record. Blattodean and mantodean appendages appear distinct in morphospace, but several appendages of fossil non-mantodeans can be considered raptorial, providing a potential transitional link between walking and raptorial morphotypes. Therefore, we discuss potential mantodean affinities for other predatory fossil dictyopterans. We examine changes across extant mantodeans, characterized by a straightening of the tibia especially associated with the rise of the diversification of the Mantidea and discuss whether a thickening of the femur could reflect an early adaptation to cursorial hunting.

Dazzled by shine: gloss as an antipredator strategy in fast moving prey.

Previous studies on stationary prey have found mixed results for the role of a glossy appearance in predator avoidance-some have found that glossiness can act as warning coloration or improve camouflage, whereas others detected no survival benefit. An alternative untested hypothesis is that glossiness could provide protection in the form of dynamic dazzle. Fast moving animals that are glossy produce flashes of light that increase in frequency at higher speeds, which could make it harder for predators to track and accurately locate prey. We tested this hypothesis by presenting praying mantids with glossy or matte targets moving at slow and fast speed. Mantids were less likely to strike glossy targets, independently of speed. Additionally, mantids were less likely to track glossy targets and more likely to hit the target with one out of the two legs that struck rather than both raptorial legs, but only when targets were moving fast. These results support the hypothesis that a glossy appearance may have a function as an antipredator strategy by reducing the ability of predators to track and accurately target fast moving prey.

Predatory influence of dragonfly larvae and water scorpions on eggs and tadpoles of Indosylvirana temporalis (Anura: Ranidae)

We assessed in the laboratory the vulnerability of Bronzed frog (Indosylvirana temporalis) eggs and tadpoles to two potential sit-and-wait insect predators, larvae of a dragonfly (Pantala flavescens; Odonata: Libellulidae) and adult water scorpions (Laccotrephes sp.; Hemiptera: Nepidae). We exposed a series of different developmental stages of I. temporalis (from eggs to metamorphic climax stage) to these two predators. The results of this study showed that larvae of P. flavescens preyed on eggs and tadpoles of I. temporalis but only to stage 36. Laccotrephes sp. did not prey on eggs of I. temporalis but on tadpoles of all stages (22 to 42). This difference in predation rate was likely due to the gape size of the predators. The larvae of P. flavescens are gape-limited and cannot prey on larger tadpoles (above stage 36). Adults Laccotrephes sp. are non-gape-limited predators, using a segmented beak to pierce I. temporalis and suck the body fluids. They captured small to large tadpoles by quickly grabbing and immobilizing them using the front pair of raptorial legs. The present study shows that both predatory insects are a threat to I. temporalis at early and later stages of larval development.

The first adult mantis lacewing from Baltic amber, with an evaluation of the post-Cretaceous loss of morphological diversity of raptorial appendages in Mantispidae

Mantis lacewings (Neuroptera: Mantispidae) are prominent and charismatic predatory representatives of Insecta. Nevertheless, representatives of the group are surprisingly scarce in Paleogene deposits after a relative abundance of specimens known from Cretaceous. Here we present Mantispa? damzenogedanica sp. nov., representing the first adult of Mantispidae described from Baltic amber and the only Eocene adult mantispid hitherto preserved in amber. The new fossil species is also among the earliest representatives of Mantispinae, certainly the oldest adult of this group described from amber. Additionally, we discuss the changes through time in the ecological morphospace within Mantispidae based on the morphological diversity (≈disparity) of the raptorial legs. Possible explanations for the post-Cretaceous decline in the morphological diversity of mantis lacewings are posited.

The first predatory dance fly of the subfamily Ocydromiinae with specialized, raptorial legs in mid–Cretaceous amber from Myanmar (Diptera: Hybotidae)

The first ocydromiine hybotid fly is described and illustrated from a remarkable male preserved in mid-Cretaceous amber from northern Myanmar. Pouillonhybos venator, gen. et sp. nov., is distinguished from other members of the subfamily Ocydromiinae as well as other lineages of living and fossil Hybotidae. The holotype of P. venator exhibits spectacular specializations of the mid and hind legs, modifications likely linked to the grasping of prey either during capture and/or while feeding. The species reported here is the earliest evidence of significant leg modifications in Hybotidae indicating an early appearance of such specializations in the family's history.

Chulacaridae, a new family of prostigmatic mites (Acari, Trombidiformes) from Thailand.

A new family of prostigmatic mites (Acari: Trombidiformes), Chulacaridae n. fam. based on Chulacarus elegans n. g. et n. sp., is described from adult females and immature instars collected from soil and litter in Thailand. The new family is monobasic and is placed in the hyporder Anystae (sensu Zhang et al. 2011), and tentatively grouped with other families in the superfamily Anystoidea. In addition to the typical features of Anystina, Chulacaridae n. fam. is characterized by the presence of enlarged, raptorial legs I uniquely with bipectinate setae on their anterior face, the presence of thick and blunt adoral setae (or1 and or2), the fusion of the palpal femur and genu, the absence of any femoral subdivision of legs I-IV, the presence of 8-10 pairs of small genital papillae, and the presence of unipectinate claws (without empodium) on pretarsi I and normal claws (with claw-like empodium) on pretarsi II-IV. Some morphological characters and its systematic position are discussed.

Kinematic Manipulability of Multi-joint Bio-inspired Extremities

A linearised navigation control law for multi-legged walking robots is presented. The proposed model is stated in terms of robot's global acceleration, and formulated as an average of the Cartesian speeds of n-extremities of k-DOFs each. The state vector is defined as a general solution scoping three cases of robot's tangential acceleration: uniform, non-uniform, and constant speed. Leg's Cartesian velocities are described by their first order Jacobian, which results in redundant kinematics systems. As particular cases of study, two different biological kinematic configurations were analysed in order to be adapted (DOFs reductions) as potential kinematic functions of the navigation control law. Although, the research interest is centralised on walking systems, the Praying-Mantis raptorial legs, as well as the Smithi ant's legs are analysed. Because of the kinematic redundancy, by using pseudo-inverse numerical methods, the solution near a singularity region is unstable about these values. It was obtained the first-order derivative pseudo-inverse Jacobian matrix using two different numerical methods for multi-joint legs: the right pseudo-inverse, and by singularity properties using the singular value decomposition approach.

On the evolution of raptorial legs - an insect example (Hemiptera: Reduviidae: Phymatinae).

The presence of chelate and subchelate fore legs in Phymatinae (Hemiptera: Reduviidae), or ambush bugs, provides a unique opportunity to study the evolution of different types of raptorial legs in a closely related group of arthropods. Themonocorini have simple, possibly raptorial legs, Phymatini and Macrocephalini distinct subchelate fore legs, and the charismatic Carcinocorini are the only insects with a chelate fore leg apart from female dryinid Chysidoidea (Hymenoptera). Relationships between the four phymatine tribes are here analyzed in a cladistic framework thus permitting testable hypotheses on the evolution of raptorial legs. The presented analysis of phymatine tribal level relationships is based on a dataset comprising 11 species of Phymatinae and 54 non-phymatine Reduviidae and Heteroptera. The molecular data set consists of ∼3500 MAFFT aligned bases of 16S, 28S D2-D3, and 18S ribosomal genes. Parsimony and maximum likelihood analyses resulted in identical topologies for the ingroup with the relationships Themonocorini + (Phymatini + (Carcinocorini + Macrocephalini)) receiving high support values. Eleven morphological characters, eight of them derived from fore leg morphology, were optimized on the parsimony analysis. These optimizations indicate that the ancestral ambush bug had a simple raptorial leg; that size reduction of the tarsus, enlargement of the femur, curvature of the fore tibia, armature of tibia and femur with rows of tiny tubercles that allow for gripping of a prey insect, and the large process on the ventral surface of the femur arose in the common ancestor of Carcinocorini + Macrocephalini + Phymatini. The chelate leg in Carcinocorini is likely derived from a subchelate precursor similar to the one seen in recent Macrocephalini and may have evolved through elongation of the ventral, proximal portion of the fore femur and modification of the median process to form part of the digitus fixus. © The Willi Hennig Society 2010.

Predatory behaviour of some Central European pselaphine beetles (Coleoptera: Staphylinidae: Pselaphinae) with descriptions of relevant morphological features of their heads

The Pselaphinae is a large subfamily of staphylinid beetles with a characteristic habitus and small body size. Detailed morphological and behavioural studies on these beetles are scarce. In this study, specimens of Bryaxis puncticollis (Denny, 1825), Bryaxis bulbifer (Reichenbach, 1816), Bythinus burrelli (Denny, 1825), Brachygluta fossulata (Reichenbach, 1816), Rybaxis longicornis (Leach, 1817), Pselaphus heisei (Herbst, 1792) and Tyrus mucronatus (Panzer, 1803), all collected in Northern Germany, have been examined with regard to their sensory organs (eyes and antennae), mouthparts and method of capturing prey. Scanning electron microscope studies revealed sex-specific differences in the numbers of ommatidia in Bryaxis puncticollis. A multitude of different sensilla on the antennae and great differences in the shape of the mouthparts were observed and peculiarities of the antennae and maxillary palps (e.g., the segment-like appendage) were examined using scanning and transmission electron microscopy. The prey-capture behaviour of these species is described in detail for the first time based on laboratory experiments using Heteromurus nitidus (Templeton, 1835) (Collembola) as prey. This behaviour seems to be tribe specific, ranging from simple seizure with the mandibles (e.g., Rybaxis longicornis, tribe Brachyglutini) to the employment of raptorial legs (Tyrus mucronatus, tribe Tyrini). The two Bryaxis species (tribe Bythinini) even employ their apparently sticky maxillary palps to capture prey. The assumption that a viscous secretion is used by these species is supported by the finding of glandular structures in the interior of their maxillary palps. Prey-capture is preceded by a complicated preparation phase in most of the species and followed by a sequence of prey-handling movements that seem to be adapted to restrain prey such as Collembola. In simple prey-choice experiments the beetles of several species preferred small prey, irrespective of their own body size. In these experiments, Bryaxis bulbifer and Brachygluta fossulata were more successful in capturing prey than Bryaxis puncticollis and Pselaphus heisei. This might be related to their different sensory equipment and different methods of capturing prey.

Variation in the geometry of foreleg claws in sympatric giant water bug species: an adaptive trait for catching prey?

AbstractWhen giant water bugs (Heteroptera: Belostomatidae) encounter prey animals that are larger than they are themselves, they first hook the claw of their raptorial legs onto the animal, and then use all their legs to pin it. The claws of the raptorial legs in giant water bugs play an important role in catching larger prey, but the relationship between the claws, body lengths of predators, and prey size has not been fully investigated. To elucidate the functioning of claws in catching prey, we investigated prey body size relative to predator size in nymphs of two sympatric belostomatid giant water bug species, the vertebrate eater Kirkaldyia (=Lethocerus) deyrolli Vuillefroy and the invertebrate eater Appasus japonicus Vuillefroy, captured in rice fields. The younger nymphs of K. deyrolli caught preys that were larger than themselves, whereas those of A. japonicus caught preys that were smaller. Younger nymphs of K. deyrolli had claws that were curved more sharply than those of A. japonicus. The more curved claws of younger nymphs of K. deyrolli probably hook more easily onto larger vertebrates and thus this shape represents an adaptation for acquiring such prey.

Gimbals in the insect leg

We studied the common kinematic features of the coxa and trochanter in cursorial and raptorial legs, which are the short size of the podomers, predominantly monoaxial joints, and the approximate orthogonality of adjacent joint axes. The chain coxa-trochanter with its short elements and serial orthogonality of joint axes resembles the gimbals which combine versatility and tolerance to external perturbations. The geometry of legs was studied in 23 insect species of 12 orders. Insects with monoaxial joints were selected. The joint between the trochanter and the femur (TFJ) is defined either by two vestigial condyles or by a straight anterior hinge. Direction of the joint axes in the two basal podomers was assessed by 3D measurements or by goniometry in two planes. Length of the coxa is <15% (mostly <8%) of the total length of the cursorial leg, that of the trochanter <10%. Angles between the proximal and distal joint axes in the middle coxa range from 124 to 84° (mean 97 ± 14°), in the trochanter (in all legs studied) from 125 to 72° (mean 90 ± 13°). Vectors of the distal axis in the coxa are concentrated about the normal to the plane defined by the proximal axis and the midpoint between the distal condyles. These vectors in the trochanter lie at various angles to the normal; angles are correlated with the direction of the TFJ relative to the femur. Range of reduction about the TFJ is over 60° in the foreleg of Ranatra linearis, Mantispa lobata and the hind leg in Carabus coriaceus (confirming observations of previous authors), 40–60° in the foreleg of Vespa crabro and in the middle one in Ammophila campestris, 10–30° in other studied specimens. The special role of the trochanter in autotomy and in active propulsion in some insect groups is discussed. The majority of insects possess small trochanters and slightly movable TFJs with the joint axis laying in the femur-tibia plane. We pose the hypothesis that the TFJ damps external forces, the vectors of which lie off the femur-tibia plane, the reductor muscle acting as a spring. Thus the TFJ contributes to dynamic stability of legged locomotion.

Colonization of the salivary glands of Naucoris cimicoides by Mycobacterium ulcerans requires host plasmatocytes and a macrolide toxin, mycolactone

Mycobacterium ulcerans was first identified as the causative agent of Buruli ulcer; this cutaneous tissue-destructive process represents the third most important mycobacterial disease in humans after tuberculosis and leprosy. More recently other life traits were documented. M. ulcerans is mainly detected in humid tropical zones as part of a complex ecosystem comprising algae, aquatic insect predators of the genus Naucoris, and very likely their vegetarian preys. Coelomic plasmatocytes could be the first cells of Naucoris cimicoides to be involved in the infection process, acting as shuttle cells that deliver M. ulcerans to the salivary glands as suggested by both in vitro and in vivo approaches. Furthermore, a key element for the early and long-term establishment of M. ulcerans in Naucoridae is demonstrated by the fact that only mycolactone toxin-producing M. ulcerans isolates are able to invade the salivary glands, a site where they proliferate. Later, the raptorial legs of Naucoris are covered by M. ulcerans-containing material that displays features of biofilms.

The Feeding Behaviour of a Sit-and-Wait Predator, Ranatra Dispar, (Heteroptera: Nepidae): Description of Behavioural Components of Prey Capture, and the Effect of Food Deprivation On Predator Arousal and Capture Dynamics1)

[The components in the predatory behaviour of this typical sit-and-wait predator are described. The sequence of components follow a basic pattern, i.e. initial precapture posture, arousal, orientation, capture, consolidation of grip, exploration, injection of venom/enzymes, feeding, discard of prey. When tested with model prey of no nutritional value following increasing periods of fast R. dispar increased the initial exploratory time and the number of exploratory bouts before rejecting the prey. The predators arousal space is elliptical horizontally and almost circular vertically, the distance being greatest in front of the predator and decreasing to the rear. The strike and capture space of R. dispar is restricted to the space anterior to the predator and bounded by approximately 45° either side horizontally and 90° to -45° (315°) vertically. Both the arousal and strike space increase with food deprivation. The period of food deprivation significantly affects the strike distance up to a maximum of about 30 mm after a 120 hour fast. Presentation along some paths evokes more strikes, hits and captures than presentation along others, suggesting that there is an optimum region within the strike space where the capture efficiency is highest. Prey moving along the 0° path in the horizontal plane or either the 0° or 45° path in the vertical plane, evoke the highest number of strikes, and hits in well-fed predators, while the highest capture efficiency occurs when prey are moved on the 0° path. Following longer periods of fasting (> 72 hours) prey moved below the 0° axis (Vertical Plane) along the -45° (315°) path evoke as many strikes as the 0° and 45° paths. Although dynamic, the capture space is limited by the reach of the raptorial legs, there being no lunge or pursuit. The capture efficiency is about 76% and unaffected by food deprivation., The components in the predatory behaviour of this typical sit-and-wait predator are described. The sequence of components follow a basic pattern, i.e. initial precapture posture, arousal, orientation, capture, consolidation of grip, exploration, injection of venom/enzymes, feeding, discard of prey. When tested with model prey of no nutritional value following increasing periods of fast R. dispar increased the initial exploratory time and the number of exploratory bouts before rejecting the prey. The predators arousal space is elliptical horizontally and almost circular vertically, the distance being greatest in front of the predator and decreasing to the rear. The strike and capture space of R. dispar is restricted to the space anterior to the predator and bounded by approximately 45° either side horizontally and 90° to -45° (315°) vertically. Both the arousal and strike space increase with food deprivation. The period of food deprivation significantly affects the strike distance up to a maximum of about 30 mm after a 120 hour fast. Presentation along some paths evokes more strikes, hits and captures than presentation along others, suggesting that there is an optimum region within the strike space where the capture efficiency is highest. Prey moving along the 0° path in the horizontal plane or either the 0° or 45° path in the vertical plane, evoke the highest number of strikes, and hits in well-fed predators, while the highest capture efficiency occurs when prey are moved on the 0° path. Following longer periods of fasting (> 72 hours) prey moved below the 0° axis (Vertical Plane) along the -45° (315°) path evoke as many strikes as the 0° and 45° paths. Although dynamic, the capture space is limited by the reach of the raptorial legs, there being no lunge or pursuit. The capture efficiency is about 76% and unaffected by food deprivation.]

FEEDING AND MATING IN THE INSECTIVOROUS CERATOPOGONINAE (DIPTERA)

AbstractThe subfamily Ceratopogoninae (sensuWirth, 1965a) is probably a natural (monophyletic) group but includes both blood sucking forms (Culicoidini) and predators on small insects. The insectivorous forms consist of a diversified array of six tribes and many genera represented in moist habitats throughout the world and especially abundant at lake margins.Many predator/prey observations are recorded. The prey consists almost exclusively of the males of other Nematocera or the smaller Ephemeroptera, which the female captures in flight by entering the male (mating) swarms of these insects and hovering until in a position to strike. The initial response is to the swarm-determining landmark, and the female hovers there whether or not potential prey is in flight; groups of hovering females can be induced artificially by suitable markers. These midges themselves form male swarms which the female enters for mating, and the unique method of hunting thus follows a pattern of behaviour already established in relation to another function. The insectivorous tribes have probably been derived from the more plesiomorphic Culicoidini, but the stages in the development of their radically different manner of hunting are not clear.The characteristic form of the mouthparts in the insectivorous genera is described and figured. The prey, after capture in flight, is usually held by the raptorial legs and quickly perforated by the mandibles. A proteolytic saliva is injected and the cellular tissue, except in the longer appendages, is liquefied and sucked out. In most species a single prey individual is not sufficient for one ovarian cycle, and the midge feeds several times. There is some degree of prey specificity, based at least in part on specific responses to the swarm-marker. In several genera there are long tubular "glands" in the abdomen, often everted in flight, whose function is not clearly established. Mobbing of the predator by the intended prey (mosquitoes) is described.The distinctive feature of mating is that the female, in addition to her other prey, often eats the male during mating. Nearly all the records come from the three tribes Heteromyiini, Sphaeromiini, and Palpomyiini. In these tribes (which probably form a relatively apomorphic monophyletic group) the male is usually a dwarf, and the plumose (auditory) antenna is more or less strongly reduced. It is suggested that the female remains in hunting phase when entering her conspecific swarm and captures the male as prey, and that the typical auditory recognition of female by male has become reduced or vestigial. In the more plesiomorphic tribes Ceratopogonini and Stilobezziini the male is normal in size and the antennal plume is fully developed, as inCulicoides, and there are only two records, at most, of the male being eaten during mating.The males eaten during mating are pierced through the head and reduced to an empty cuticle by the action of the lytic saliva. The terminalia however retain their hold, perhaps because of the early destruction of the suboesophageal ganglion, and the dry male cuticle often breaks away leaving the terminalia still attached. The structure of the terminalia and the mating position is described and discussed. Insemination is by spermatophore, which if the male is eaten never leaves the male duct. The terminalia of the male are inverted during mating and in some genera become so permanently early in adult life.An attempt is made throughout to view the phenomena in a phylogenetic context.Numerous illustrations are provided.