XXXII.—Nouveaux Bruchidæ

The bush cricket Psorodonotus illyricus is indigenous to the Balkans. Singing males of this species are highly mobile. The acoustic factors which might influence the locomotion were investigated in the field. The mobility of the males results in an often random distribution pattern. Interactions between the males are purely acoustic, and the duets are characterized by periods of good and poor alternation. Playback experiments, field observations and tape recordings of duetting males indicate that singing rate and sound intensity affect alternation behaviour and locomotion. However, the effect of the two song parameters is related to the time of the day, a phenomenon which might be due to (a) changes in the sound field around a singing male, and (b) altering microclimatic factors during the activity period of the insects.     

The occurrence,mechanics and significance of burying behaviour in crabs (Crustacea: Brachyura)

Although the terms burrowing and burying are often used interchangeably in the literature, there are clear distinctions between these two types of behaviour in terms of their ecological, mechanical and physiological implications. Both types of behaviour are widely observed in the Brachyura. In comparison to the well researched area of burrowing in crabs, information on burying is relatively dispersed. This review will examine the extent of burying behaviour in brachyurans, and the physiological and ecological consequences of the behaviour within the group. At least nine of the 50 families of brachyuran crabs have either been observed to bury in soft substrata or are suspected, on morphological grounds, of burying. There appears to be no specific morphological adaptations for burying in brachyurans, apart from those features associated with respiration whilst buried in the sediment. Buried individuals must ensure constant access to oxygenated water in the face of mechanical problems resulting from direct contact with the sediment, i.e., the threat of clogging. Burying taxa deal with this challenge through accessory respiratory channels and altered respiratory rhythms. The evolutionary implication of the burying habit is equivocal. Burying taxa are amongst the most speciose and numerically dominant brachyuran groups in marine systems, all reaching their greatest diversity and abundance in soft substrata. Burying may be an ancestral condition, with many of these groups evolving in habitats characterized by soft sediment.     

Variation in spatial and temporal kinematics of level,vertical and inverted locomotion on a stinkbug Erthesina fullo

In the learning of locomotion behavior of a stink- bug Erthesina fullo, the seeked principle of its locomotion can be an important inspiration on the design of six-legged robot. To achieve this goal, in this paper, locomotion behavior of stink- bugs on glass and plastic foam are recorded. Hereby, variation in spatial and temporal kinematics of level, vertical and inverted locomotion is analyzed. Differential leg function and adhesive mechanism as well as the advantage of non-isometric legs of insects are presented. With increasing stride frequency, the speed of level, vertical and inverted locomotion can be higher without adjusting stride length. Variation in gait characteristics between level and vertical locomotion is very little, but lower speed and larger duty factor of inverted locomotion can be occurred while climbing on glass. On the surface of vertical and inverted plastic foam, stinkbugs cannot walk steady and agilely due to its adhesive mechanism.