Community Structure of Social Wasps (Hymenoptera: Vespidae) in Riparian Forest in Batayporã, Mato Grosso do Sul, Brazil

Reduction and destruction of riparian forests are harmful to the biota, especially the social wasps. This study analyzed the species constancy and the structure of the polistine wasp community associated with fragments of riparian forest in the municipality of Batayporã, state of Mato Grosso do Sul. Eighteen species of social wasps were collected, by the methods of active searching and traps baited with honey and sardine. Eight species were classified as infrequent, five as very frequent, and five as of intermediate frequency. The community structure, as represented by species richness, showed a significant negative correlation with the Berger-Parker dominance index, and no significant correlation with the width of the fragments and with the structural complexity of the vegetation, suggesting that the community, in this case, must be structured by the tolerance of the species and not by the vegetation characteristics, which did not limit the dispersal of the social wasps

Effect of Magnetic Field on the Foraging Rhythm and Behavior of the Swarm-founding Paper Wasp Polybia paulista Ihering (hymenoptera: vespidae)

The geomagnetic field can be used by insects for navigation and orientation, through different magnetoreception mechanisms. Magnetic sensitivity is very well documented in honeybees, ants and termites, but few studies have examined this capability in social wasps. The present study analyzed the magnetic sensitivity of the paper wasp Polybia paulista. The wasps' behavior was analyzed in the normal geomagnetic field and in the presence of external magnetic fields generated by permanent magnets or by Helmholtz coils. The frequency of foraging flights was measured in both conditions, and also the behavior of the individuals on the nest surface was analyzed. The magnetic field from the permanent magnet produced an increase in the frequency of departing foraging flights, and also the wasps grouped together on the nest surface in front of the magnet. The electromagnetic field created by the Helmholtz coils also increased foraging flights, but individuals did not show grouping behavior. This Helmholtz electromagnetic field induced wasp workers to perform “learning flights”. These results show for the first time that Polybia paulista wasps are sensitive to magnetic fields, including it in the list of animal models to study magnetoreception and magnetic sensitivity

Magnetosensibility and Magnetic Properties of Ectatomma brunneun Smith, F. 1858 Ants

The aim of the present paper is to study magnetosensibility and to seek for magnetic nanoparticles in ants. The social insects, by living in colonies, developed very efficient methods of nestmate recognition, being less tolerant towards individuals from other colonies. Therefore, any kind of strange behavior between nestmates and/or conspecifics, besides those present in their own behavioral repertoire, is not expected. The behavior study in the present paper analyze whether changes in the intensity of applied magnetic fields on Ectatomma brunneun (Smith) ants can cause changes in the normal pattern of interaction between conspecifics. A pair of coils generating a magnetic field was used to change the whole local geomagnetic field. Magnetometry studies were done on abdomens and head + antennae using a SQUID magnetometer. The results show that changes in the geomagnetic field affect the usual pattern of interactions between workers from different colonies. The magnetometry results show that abdomens present superparamagnetic nanoparticles and heads present magnetic single domain nanoparticles. Behavior experiments show for the first time that Ectatomma brunneun ants are magnetosensible. The change in nestmate recognition of Ectatomma ants observed while a magnetic field is applied can be associated to some kind of disturbance in a magnetosensor presented in the body based on magnetic nanoparticles

Magnetoreception in Social Wasps:: An Update

Magnetoreception is a mechanism of active orientation that occurs in animals with nervous systems. Social insects such as bees, ants, wasps and termites have been studied on the influence of the magnetic field exerts on its biology. The social wasps comprise species represented in Stenogastrinae, Vespinae and Polistinae, however studies on the influence of magnetic field on wasps Vespinae address only. The areas studied include the biomineralization of magnetic material and behavioral aspects related to changes in local intensity of the geomagnetic field. The objective of this review is to integrate knowledge of social wasps’ magnetoreception in order to build an instructive overview of the current situation of studies, therefore, provide the conceptual framework for the development of future work on the topic.Magnetorrecepção é um mecanismo de orientação ativa que ocorre em animais com sistema nervoso. Insetos sociais tais como abelhas, formigas, vespas e cupins são estudados sobre a influência que o campo magnético exerce em sua biologia. As vespas sociais compreendem espécies representadas em Stenogastrinae, Vespinae e Polistinae, no entanto os estudos sobre a influência do campo magnético em vespas abordam somente Vespinae. As áreas de estudo incluem a biomineralização do material magnético e aspectos comportamentais relacionados a mudanças na intensidade do campo geomagnético local. O objetivo desta revisão é integrar o conhecimento sobre magnetorrecepção em vespas sociais, a fim de construir um panorama elucidativo da atual situação dos estudos, e assim fornecer uma estrutura conceitual para o desenvolvimento de trabalhos futuros sobre o tema