Circulation in Insect Wings

Synopsis Insect wings are living, flexible structures composed of tubular veins and thin wing membrane. Wing veins can contain hemolymph (insect blood), tracheae, and nerves. Continuous flow of hemolymph within insect wings ensures that sensory hairs, structural elements such as resilin, and other living tissue within the wings remain functional. While it is well known that hemolymph circulates through insect wings, the extent of wing circulation (e.g., whether flow is present in every vein, and whether it is confined to the veins alone) is not well understood, especially for wings with complex wing venation. Over the last 100 years, scientists have developed experimental methods including microscopy, fluorescence, and thermography to observe flow in the wings. Recognizing and evaluating the importance of hemolymph movement in insect wings is critical in evaluating how the wings function both as flight appendages, as active sensors, and as thermoregulatory organs. In this review, we discuss the history of circulation in wings, past and present experimental techniques for measuring hemolymph, and broad implications for the field of hemodynamics in insect wings.

Seismic air guns damage rock lobster mechanosensory organs and impair righting reflex

The effects of anthropogenic aquatic noise on marine invertebrates are poorly understood. We investigated the impact of seismic surveys on the righting reflex and statocyst morphology of the palinurid rock lobster, Jasus edwardsii , using field-based exposure to air gun signals. Following exposure equivalent to a full-scale commercial assay passing within 100–500 m, lobsters showed impaired righting and significant damage to the sensory hairs of the statocyst. Reflex impairment and statocyst damage persisted over the course of the experiments—up to 365 days post-exposure and did not improved following moulting. These results indicate that exposure to air gun signals caused morphological damage to the statocyst of rock lobsters, which can in turn impair complex reflexes. This damage and impairment adds further evidence that anthropogenic aquatic noise has the potential to harm invertebrates, necessitating a better understanding of possible ecological and economic impacts.

The mechanical basis for snapping of the Venus flytrap, Darwin’s ‘most wonderful plant in the world’

ABSTRACTThe carnivorous Venus flytrap catches prey by an ingenious snapping mechanism. Based on work over the past 190 years, it has become generally accepted that two touches of the trap’s sensory hairs within 30 seconds, each one generating an action potential, are required to trigger closure of the trap. We developed an electromechanical model which, however, suggests that under certain circumstances one touch is sufficient to generate two action potentials. Using a force-sensing microrobotics system, we precisely quantified the sensory hair deflection parameters necessary to trigger trap closure, and correlated them with the elicited action potentials in vivo. Our results confirm the model’s predictions, suggesting that the Venus flytrap may be adapted to a wider range of prey movement than previously assumed.

Mesobuthus gibbosus (Brullé, 1832) (Scorpiones: Buthidae) Akrep Türünün Tarak Organının Fonksiyonel Morfolojisi ve Histolojisi

Scorpions are venomous arthropods in Arachnida classis; they are thought to be related with the spiders, ticks and mites. However, scorpions have sensory organs called sensory comb organ (pectine) and their structure are distinctive other relatives. The objective of the present study, is to characterize the morphological and histological features of pectines (sensory comb) organ of scorpion species Mesobuthus gibbosus (Brullé, 1832) (Scorpionidae: Buthidae) were identified by using light microscope and scanning electron microscope (SEM). The pectines were prepared by following routine electron microscope procedures and routine paraffin methods and the sections were stained by hematoxylin-eosin stain. The pectines of M. gibbosus are paired sensory organs located on the ventrolateral of second segments of mesosoma, the comb like each pectin organ consist of marginal lamella, different number of median lamella and teeth. Pectines have several sensory hairs and peg sensilla of tip of the tooth. The transverse sections of pectines organ were observed that each peg sensilum innerved by many sensory neurons.

Mechanosensory hairs in bumblebees (Bombus terrestris) detect weak electric fields

Bumblebees (Bombus terrestris) use information from surrounding electric fields to make foraging decisions. Electroreception in air, a nonconductive medium, is a recently discovered sensory capacity of insects, yet the sensory mechanisms remain elusive. Here, we investigate two putative electric field sensors: antennae and mechanosensory hairs. Examining their mechanical and neural response, we show that electric fields cause deflections in both antennae and hairs. Hairs respond with a greater median velocity, displacement, and angular displacement than antennae. Extracellular recordings from the antennae do not show any electrophysiological correlates to these mechanical deflections. In contrast, hair deflections in response to an electric field elicited neural activity. Mechanical deflections of both hairs and antennae increase with the electric charge carried by the bumblebee. From this evidence, we conclude that sensory hairs are a site of electroreception in the bumblebee.