Karsten Seidelmann

Martin Luther University Halle-Wittenberg | MLU · Institute of Biology

The wool carder bee Anthidium manicatum is one textbook example of resource defense polygyny among solitary bees, known for intense male–male competition, forced copulations, and the extreme form of interspecific territoriality toward other flower visitors. This mating system depends on the spatial structure of the defended resource and requires se...

The ability to recognize the own nest is a basic skill in nest constructing solitary bees. Osmia cornuta females use a dual mechanism of visual orientation to approach a nest and olfactory verification of the tube when entering it. Occupied tubular cavities were steadily marked by the resident female. Nest marking substances originate from Dufour’s...

European foulbrood (EFB), caused by Melissococcus plutonius, is a globally distributed bacterial brood disease affecting Apis mellifera larvae. There is some evidence, even if under debate, that spreading of the disease within the colony is prevented by worker bees performing hygienic behaviour, including detection and removal of infected larvae. O...

Females of many monandrous insect species announce their receptivity either by specialised sex-pheromones or by a signature mixture of cuticular hydrocarbons (CHCs). The trigger that shuts down the sex-pheromone release or initialises a change in CHC bouquet is thought to be either the mating per se or male pheromones transferred during copulation....

Resources (energy expenses) that can be devoted to progeny are always limited. Optimal resource allocation theory predicts that parents should allocate resources to their offspring in portions that maximise their own fitness returns per unit invested, not the fitness of the offspring. Females of solitary, nest‐constructing bees control the key feat...

Living in high-density groups of animals has advantages and disadvantages for mating. The advantage of facilitated mate finding is compromised by difficulties in protecting a suitable partner from competitors. Thus, males regularly are faced with increased competition for sperm, and females with harassment by males at high population densities. To...

In insects that lay eggs in large clutches, yolk accumulation in each of the many ovarioles is restricted to the basal (terminal) oocyte, the one closest to the lateral oviduct. All succeeding (subterminal) oocytes remain small until the terminal oocytes finished their development and were ovulated into the oviduct. The major step regulating yolk u...

Recent declines of bee populations have led to great interest in preserving bee species and fuel efforts to develop solitary species for pollination purposes. Xylophilous solitary bees can be easily reared in artificial nests tubes for commercial agricultural as well as wild plant pollination. The impact of the dimensions of these artificial nest t...

Males of some hymenopteran species are able to behaviourally induce unreceptivity to mating in females by a post-copulatory display (post-copulatory courtship). This method of preventing further inseminations requires a high degree of female cooperation by the female and is especially susceptible to manipulations. If mating chances are low and sexu...

Phengaris (Maculinea) butterflies are social parasites of Myrmica ant colonies. Larvae of the parasite are adopted by the ant workers into the colonies. Apparently, chemical signals are used by Phengaris nausithous Bergsträsser larvae to mimic those of the host brood to be recognized by the ants. In the present study, chemical extracts of ant brood...

In monandrous species, females have to manage their mating receptivity not only to gather an appropriate sperm supply, but to avoid further male sexual harassment as well. The shutdown of female receptivity to mating is often an irreversible process and therefore should result from a reliable signal. Females of the red mason bee, Osmia bicornis (sy...

1. Females of solitary, nest-constructing bees determine both sex (haplo-diploidy) as well as body size (by amount of provision) of each single offspring.2. According to the Optimal Allocation Theory, females should allocate resources in portions that maximise fitness returns. A key fitness component in bees is body size that is determined solely b...

Accurate mass spectra of compounds 1-3 measured on Masspec GC-MS instrument; Peak 1 NIST database hit (Purity/Mixture) 961/963 for 2-octen-1-ol, peak 2 hit 983/983 for nonanal and the major peak 3 hit 989/989 for 3-nonen-1-ol

Adducts of acetylation and following DMDS derivatisation of (Z)-3-nonen-1-ol (a) and (Z)-2-octen-1-ol

Pheromones serve key functions in the biology of swarming locusts. However, research has focused largely on the mass-swarming desert locust, Schistocerca gregaria. We extended these investigations to the pheromonal profile of the rarely swarming American bird grasshopper, S. americana (Drury). The headspace of mature gregarious S. americana males c...

Trivers' and Willard's hypothesis that natural selection favors sex allocation in relation to maternal condition assumes iteropary. Though this assumption is not met in most solitary Aculeata, the reproductive life span of semelparous females may be divided into discrete successive cycles by the risk of open-cell parasitism. Females can avoid losin...

Abstract The haemolymph titre of the phase-related 6-kDa peptide is determined in fourth- and fifth-instar larvae, as well as in adults, by high-performance liquid chromatography. In larvae, the concentration of this peptide slowly increases towards the end of the instar to reach a maximum just before the moult. The titre is slightly higher in the...

Gregarious mature males of the desert locust (Schistocerca gregaria) emit a courtship-inhibiting pheromone continuously to repel rivals. This signal evokes a strong response from males with recent experience of mature females. However, if males have been female deprived for some time, they start to ignore the pheromone and attempt to usurp females...

Brood cell parasitism inflicts high fitness costs on solitary, nest-constructing bees. Many of these parasites enter open cells during its provisioning, when the mother bee is absent. Therefore, females can reduce the risk of open-cell parasitism by limiting the time they are away from the nest. However, provisioning efficiency (provisioning time p...

Microsatellite loci were isolated from the solitary Red Mason bee (Osmia rufa) by an enrichment protocol for partial genomic libraries. Six polymorphic microsatellite loci were used for a first population structure survey including 9 continental European and one island population. Observed levels of genetic variability and heterozygosity proved to...

The behavioural response of desert locust individuals to adult male volatiles had been investigated in a dynamic Y-T-olfactometer. Synthetic blends of a postulated adult male-produced aggregation pheromone with or without phenylacetonitrile were not attractive to fifth-instar nymphs, young or mature adults of both sexes. Instead phenylacetonitrile...

The propagation of the alfalfa leaf-cutter bee, Megachile rotundata was tested from 1988 to 1991 on alfalfa seed growing fields at the Uvs-Nuur Basin in the North-West of Mongolia. We used the loose-cell technology in combination with wooden grooved boards (dimensions of the nesting holes: 8 × 110 mm). The climatic conditions at the investigation a...

Physocephala pusilla Meigen (Diptera: Conopidae) was found to be a dangerous endoparasitoid of the alfalfa leafcutter bee Megachile rotundata F. (Hymenoptera: Megachilidae) in Mongolia. The conopid fly parasitizes adults and causes their early death. In 1989 and 1990, 16% and 15% respectively of the M. rotundata females were found dead in front of...

Mature gregarious male desert locusts, Schistocerca gregaria, emit the courtship inhibition pheromone phenylacetonitrile. Wings and legs, in particular the fore wings, have been identified as the main releasing sites. Abdomen and head emit only trace amounts of this pheromone. In contrast veratrole, another typical component of male volatiles, is e...

Desert locusts, Schistocerca gregaria (Forskål) (Orthoptera: Acrididae), exhibit a population density-dependent phase polymorphism which includes the gradual change of many morphological, physiological and behavioural characteristics. Many volatiles associated with desert locusts have been identified recently and it is assumed that they are involve...

Male desert locusts in the gregarious phase release phenylacetonitrile (PAN) on becoming sexually mature. It has been assumed that this chemical is responsible for aggregation of adult desert locusts. However, PAN has repellent characteristics and is involved in sexual behavior. Mature males release PAN as a volatile to serve as a kind of olfactory...

Ulbrich, K. and Seidelmann, K. 2001. Modeling population dynamics of solitary bees in relation to habitat quality. - Web. Ecol. 2: 57-64. To understand associations between habitat, individual behaviour, and population de- velopment of solitary bees we developed an individual-based model. This model is based on field observations of Osmia rufa (L)...

Volatiles emanating from living Schistocerca gregaria at various stages of development were trapped by means of a closed-loop-stripping system. Benzyl cyanide was previously identified with GC-MS methods as a volatile that was exclusively released by adult mature gregarious males. The amount of BC released depended on the number of males per group....

The ecology of a species strongly influences the strategies with which males and females maximize their lifetime reproductive success. When males and females do not invest equally in offspring, the sex with the higher parental investment becomes a rare resource for the other. The spatial and temporal distribution of the limiting sex forms the basis...

Nests of the stem- or hole-nesting megachilid bee, Osmia rufa, were analysed to help clarify the function of the outermost empty chamber of the nest, the vestibulum. Only nests in an exposed nesting environment had a long vestibulum, whereas nests protected from sun and temperature fluctuations (within a honey bee hive body) had short vestibuli or...

Regulation mechanisms of pheromone release in males of the desert locust, Schistocerca gregaria. Male desert locusts in the gregarious phase release phenylacetonitrile (PAN) when becoming sexually mature and turning yellow. The pheromone has repellent characteristics toward conspecifics. PAN is used by males in dense populations as a courtship inhi...