@article{Mahsberg1986, author = {Mahsberg, Dieter}, title = {Contact chemoreception of prey in hunting scorpions}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-45784}, year = {1986}, abstract = {Scorpions commonly are assumed to hunt on living prey. But under laboratory conditions they also respond very sensitively to dead insects lying on the substrate. In many cases the motionless prey is seized and consumed. It was investigated how this behavior can be elicited. The buthid scorpions Androctonus australis (L.) and Buthus occitanus (Am.) not only find motionless prey again which was stung but managed to escape before dying: They also respond to extracts of the cuticle of prey insects. After touching prey marks' either with the tips of the chelae fingers or the tarsi of the walking legs or the pectine organs specific responses (searching, seizing, feeding) are released at a high rate. Behavioral experiments demonstrate for the first time the chemosensitivity of the pectine organs for which only mechanosensitivity had been proofed formerly. Mechanical as well as contact chemical stimulation of these organs cause scorpions to orient towards the stimulus source which is grasped, retained and consumed or rejected depending on its quality. The probably responsible chemosensitive receptors are already described in the literature. The possible adaptive value and the biological significance of contact chemoreception in prey catching and in other aspects of the life of scorpions is discussed.}, subject = {Skorpion}, language = {en} } @article{Linsenmair1985, author = {Linsenmair, Karl Eduard}, title = {Individual and family recognition in subsocial arthropods, in particular in the desert isopod Hemilepistus reaumuri}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33957}, year = {1985}, abstract = {Individual recogmtlon in the non-eusocial arthropods is, according to our present knowledge, predominantly found in the frame of permanent or temporary monogamy. In some cases, e. g. in stomatopods and possibly other marine crustaceans too, individual recognition may serve to allow identification of (i) individuals within dominance hierarchies or (ii) neighbours in territorial species thus helping to avoid the repetition of unnecessary and costly fights. Kin recognition is experimentally proven only in some isopod species (genera Hemilepistus and Porcel/io) and in the primitive cockroach (termite?) Cryptocercus. The «signatures» or «discriminators» used in the arthropods are chemical. It is assumed that the identifying substances are mainly genetically determined and in this paper I shall discuss possible evolutionary origins. The main part of this account is devoted to the presentation of some aspects of the highly developed individual and kin identification and recognition system in the desert isopod Hemilepistus reaumuri - a pure monogamous species in which pairs together with their progeny form strictly exclusive family units. Amongst other things problems of (i) mate choice, (ii) learning to recognize a partner, (iii) avoiding the un adaptive familiarization with aliens are treated. Monogamy under present conditions is for both sexes the only suitable way of maximizing reproductive success; an extremely strong selection pressure must act against every attempt to abandon monogamy under the given ecological conditions. The family «badges» which are certainly always blends of different discriminator substances are extremely variable. This variability is mainly due to genetical differences and is not environmentally caused. It is to be expected that intra-family variabiliry exists in respect of the production of discriminator substances. Since the common badge of a family is the result of exchanging and mixing individual substances, and since the chemical nature of these discriminators requires direct body contacts in order to acquire those substances which an individual does not produce itself, problems must arise with molting. These difficulties do indeed exist and they are aggravated by the fact that individuals may produce substances which do not show up in the common family badge. An efficient learning capability on the one hand and the use of inhibiting properties of newly molted isopods help to solve these problems. In the final discussion three questions are posed and - partly at least - answered; (i) why are families so strictly exclusive, (ii) how many discriminator substances have to be produced to provide a variability allowing families to remain exclusive under extreme conditions of very high population densities, (iii) what is the structure of the family badge and what does an individual have to learn apart from the badge in order not to mistake a family member for an alien or vice versa.}, language = {en} } @incollection{WarburgLinsenmairBercovitz1984, author = {Warburg, M. R. and Linsenmair, Karl Eduard and Bercovitz, K.}, title = {The effect of climate on the distribution and abundance of isopods}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-44473}, publisher = {Universit{\"a}t W{\"u}rzburg}, year = {1984}, abstract = {Climate affects both the distribution and abundance of isopods. Humidity and moisture affect their activity and distribution. Survival of juveniles is largely dependent on moisture. The reproductive pattern is affected by temperature and light. Food affects growth and thus, indirectly, also reproduction, as larger females tend to produce larger broods and more frequent broods than smaller ones. Generally in isopods there is little evidence to suggest that food is a very important factor affecting their abundance. Both semelparity and iteroparity are found in isopods and both reproductive strategies are apparently successful. Mortality factors affect the oocytes, the marsupial stages, and most of all the newly released individuals . Apart from climatic factors, predation and, to a lesser extent, parasitism are the main causes of mortality. Longevity of isopods ranges from one to five years. Occasional population explosions ofisopods are known to take place, their cause being unknown.}, language = {en} } @article{Linsenmair1984, author = {Linsenmair, Karl Eduard}, title = {Comparative studies on the social behaviour of the desert isopod Hemilepistus reaumuri and of a Porcellio species}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30846}, year = {1984}, abstract = {Behavioural adaptations have made the desert isopod Hemilepistus reaumuri the most successful herbivore and detritivore of the macrofauna of many arid areas in North Africa and Asia Minor. For survival and reproduction Hemilepistus is dependent on burrows. New burrows can only be dug during spring. With the time-consuming digging of a burrow, Hemilepistus has only made the first step towards solving its ecological problems. The burrows are vital and have to be continuously defended against competitors. This requirement is met by co-operation of individuals within the framework of a highly developed social behaviour. In spring adults form monogamous pairs in which partners recognize each other individually and later form, with their progeny, strictly closed family communities. Hemilepistus is compared with a Porcellio' sp. which has developed, convergently, a social behaviour which resembles that of Hemilepistus in many respects, but differs essentially in some aspects, partly reflecting differences in ecological requirements. This and a few other Porcellio species demonstrate some possible steps in the evolution of the social behaviour of Hemilepistus. The female Hemilepistus is-in contrast to Porcellio sp. - semelparous and the selective advantages of monogamy in its environment are not difficult to recognize. This chapter discusses how this mating system could have evolved and especially why monogamous behaviour is also the best method for the Hemilepistus male to maximize its reproductive success. The cohesion of pairs and of family communities in Hemilepistus is based on a highly developed chemical communication system. Individual- and family-specific badges owe their specificity to genetically determined discriminating substances. The nature of the badges raises a series of questions: e.g. since alien badges release aggression, how do parents avoid cannibalizing their young? Similar problems arise from the fact that family badges are mixtures of chemical compounds of very low volatility with the consequence that they can only be transferred by direct contact and that during moulting all substances are lost which an individual does not produce itself. It is shown that in solving these problems inhibiting properties (presumably substances) and learning play a dominant role.}, language = {en} } @article{MeyerSchartl1984, author = {Meyer, Manfred K. and Schartl, Manfred}, title = {Pseudotropheus (Maylandia) hajomaylandi n. sp., a new taxon from Lake Malawi}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-70989}, year = {1984}, abstract = {Pseudotropheus hajomaylandi (loc. typ. Isle of Chisumulu, Lake Malawi) is described as a new species. It is compared with Ps. aurora, Ps. greshakei, Ps. livingstonii, Ps. lombardoi, and Ps. zebra. All these taxa, including Ps. hajomaylandi and Ps. heteropictus, are classified in the subgenus Maylandia.}, subject = {Buntbarsche}, language = {en} } @article{Linsenmair1974, author = {Linsenmair, Karl Eduard}, title = {Some adaptations of the desert woodlouse Hemilepistus reaumuri (Isopoda, Oniscoidea) to desert environment}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-44483}, year = {1974}, abstract = {No abstract available}, language = {en} } @article{Linsenmair1972, author = {Linsenmair, Karl Eduard}, title = {Anemomenotactic orientation in beetles and scorpions}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-78118}, year = {1972}, abstract = {Scorpions, living in North African semideserts are - in spite of disrupting experimental interferences - able to maintain a certain direction in their natural environment in the dark on a plane surface. Under comparable laboratory conditions, excluding the possibility of light or gravity orientation, they can orient themselves if a directed air current passes over the "arena." In most cases the scorpions do not run necessarily with or against the wind, but rather maintain constant angles to the air current for anywhere from minutes to many hours. They are running anemomenotactically (ref. 1). Under identical conditions many species of beetles also orient themselves to air currents (refs. 2 to 4). The main problems to be solved in the study of anemomenotactic orientation are: (1) Which physical qualities of the air current have an influence on the anemomenotaxis? (2) With which sense organs do beetles and scorpions perceive wind directions? (3) Which physiological mechanism is the basis of anemomenotactic orientation? (4) What is the biological significance of anemomenotaxis in beetles and scorpions? With respect to these problems, more study has been done on beetles than on scorpions. Therefore, due to lack of space, I shall discuss mainly some of the results obtained in experiments with dung beetles (Geotrupes silvaticus, G. ,Stercorarius, G. armifrons, G. niger, Scarabaeus variolosus) and tenebrionid beetles (Tenebrio molitor, Pimelia grossa, P. tenuicomis, Scaurus dubius).}, subject = {Biologie}, language = {en} }