Vibrational communication facilitates cooperative foraging in a phloem-feeding insect

Insects are the dominant herbivores in tropical forests, with a range of mechanisms for exploiting plant resources. For group-living species, such mechanisms may involve communication. The Neotropical treehopper Calloconophora pinguis (Hemiptera: Membracidae) is a sap-feeding species in which groups of siblings feed on new leaves during the brief period of leaf expansion. Using an experimental approach, a process of cooperative foraging among siblings was documented, in which a few individuals in a group behave as scouts, locating a new feeding site and advertising it using plant-borne vibrational signals. Signalling leads to a period of positive feedback in which newly recruited individuals signal in concert with those already there. The food signalling system of C. pinguis is unique in its use of synchronized group displays and in the tight coordination of receiver responses with collective signals. Examples from a number of taxonomic groups show that vibrational communication can allow group-living insects to solve the challenges of feeding on plants, such as remaining in a foraging group or avoiding predation. While most research has focused on leaf-feeding species, sap-feeding species may remove just as much biomass. This study shows that cooperative vibrational communication underlies the ability of a sap-feeding species to exploit plant resources during a narrow window of availability

Neurophysiology of insects using microelectrode arrays: Current trends and future prospects

Simple to complex behaviors are directed by the brain, which possess nervous cells, called neurons. Mammals have billions of neurons, organized in networks, making their study difficult. Although methods have well evolved since the last century, studying a simpler model is the key to resolving neuronal communication. In this review, we demonstrate that insects are an excellent model and tool to understand neural mechanisms. Moreover, new technology, such as Microelectrodes Arrays (MEAs), is an innovative method which opens the possibility to study neuron clusters, rather than individual cells. A combined method of an insect model and MEAs technology may lead to great discoveries in neurophysiology, advancing progress in pharmacology, infectious and neurodegenerative diseases, agriculture maintenance and robotics

Endothermy and chorusing behaviour in the African platypleurine cicada Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae)

Cicadas use acoustic signals to find mates and therefore offer a phylogenetically independent opportunity to test the generality of ideas about acoustic communication that were developed from studies of other animals. Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae) is a forest-dwelling platypleurine cicada that uses its calling song to form choruses and attract mates. Additionally, P. semiclara produces an encounter call that is involved in courtship and also in spacing males within choruses. Males generally call from exposed trunks and branches within the understory but clear of the undergrowth and fight with other males that call within about 50 cm of them. Choruses sing sporadically throughout the day but focus most of their calling activity into half-hour bouts at dawn and dusk. Body size and ambient temperature had no significant effect on spectral or temporal characteristics of the calling song. Body temperature measurements indicate that P. semiclara thermoregulates endothermically, with a body temperature of more than 22 °C above ambient temperature being measured during calling activity at dusk. Such endothermy provides an advantage to the cicadas by allowing them to call during crepuscular hours when atmospheric conditions are most optimal for acoustic communication and predation risks are minimal. Coincidentally, endogenously regulating body temperature allows the temporal characteristics of the call to be unaffected by ambient temperature changes

Self-organisation of symbolic information

Information is encountered in two different appearances, in native form by arbitrary physical structures, or in symbolic form by coded sequences of letters or the like. The self-organised emergence of symbolic information from structural information is referred to as a ritualisation transition. Occurring at some stage in evolutionary history, ritualisation transitions have in common that after the crossover, arbitrary symbols are issued and recognised by information-processing devices, by transmitters and receivers in the sense of Shannon's communication theory. Symbolic information-processing systems exhibit the fundamental code symmetry whose key features, such as largely lossless copying or persistence under hostile conditions, may elucidate the reasons for the repeated successful occurrence of ritualisation phenomena in evolution history. Ritualisation examples are briefly reviewed such as the origin of life, the appearance of human languages, the establishment of emergent social categories such as money, or the development of digital computers. In addition to their role as carriers of symbolic information, symbols are physical structures which also represent structural information. For a thermodynamic description of symbols and their arrangements, it appears reasonable to distinguish between Boltzmann entropy, Clausius entropy and Pauling entropy. Thermodynamic properties of symbols imply that their lifetimes are limited by the 2nd law