The eversible tentacle organs of Polyommatus caterpillars (Lepidoptera, Lycaenidae): Morphology, fine structure, sensory supply and functional aspects.

In their late (3rd and 4th) larval stages, caterpillars of the myrmecophilous lycaenid (Lepidoptera) species Polyommatus coridon and Polyommatus icarus, possess on their 8th abdominal segment two eversible so called tentacle organs (TOs). Previous histological and behavioural results have proposed that the TOs may release a volatile substance that elicits "excited runs" in attendant ants. In our study we investigated for the first time the temporal in- and eversion pattern of TOs.

A new kind of auxiliary heart in insects: functional morphology and neuronal control of the accessory pulsatile organs of the cricket ovipositor.

Introduction: In insects, the pumping of the dorsal heart causes circulation of hemolymph throughout the central body cavity, but not within the interior of long body appendages. Hemolymph exchange in these dead-end structures is accomplished by special flow-guiding structures and/or autonomous pulsatile organs ("auxiliary hearts"). In this paper accessory pulsatile organs for an insect ovipositor are described for the first time.

Variations in interpulse interval of double action potentials during propagation in single neurons.

In this work, we analyzed the interpulse interval (IPI) of doublets and triplets in single neurons of three biological models. Pulse trains with two or three spikes originate from the process of sensory mechanotransduction in neurons of the locust femoral nerve, as well as through spontaneous activity both in the abdominal motor neurons and the caudal photoreceptor of the crayfish. We show that the IPI for successive low-frequency single action potentials, as recorded with two electrodes at two different points along a nerve axon, remains constant.

Giant and dwarf axons in a miniature insect, Encarsia formosa, (Hymenoptera, Calcididae).

Miniaturization effects in the central nervous system (CNS) of a very small calchicid wasp, Encarsia formosa (0.6 mm long), are obvious for the overall morphology and at the level of axon sizes. Parasagittal sections show that most ganglia are fused and leave connectives only in the neck and the petiole.

Spontaneous behavioral rhythms in the isolated CNS of insects - presenting new model systems.

Three new model systems for the study of rhythm generation in the isolated insect central nervous system are presented. Natural behavioral rhythms are produced in these cases spontaneously in the isolated CNS. They can be monitored as output of motoneurons at peripheral nerves.