Filtern
Volltext vorhanden
- ja (26)
Gehört zur Bibliographie
- ja (26)
Erscheinungsjahr
Dokumenttyp
Sprache
- Englisch (26) (entfernen)
Schlagworte
- cuticular hydrocarbons (6)
- chemical communication (3)
- speciation (3)
- Formicidae (2)
- Hymenoptera (2)
- bees (2)
- chemical mimicry (2)
- ecology (2)
- formicidae (2)
- global change (2)
- hymenoptera (2)
- pheromones (2)
- plant-insect interactions (2)
- Alpine habitats (1)
- Ameisen (1)
- Anoplolepis gracilipes (1)
- Apidae (1)
- Apis dorsata (1)
- BETA-Diversität (1)
- BETA-Multifunktionalität (1)
- BayPass (1)
- Beauveria bassiana (1)
- Bees (1)
- Bembix (1)
- Biodiversität (1)
- COI (1)
- Chemical composition (1)
- Chemische Kommunikation (1)
- Chrysididae (1)
- Conifers (1)
- Cryptic species (1)
- Dufours gland (1)
- European orchard bee (Osmia cornuta) (1)
- Forests (1)
- Forschungsstation Fabrikschleichach (1)
- Fungal cell-walls (1)
- Halictidae (1)
- Hautflügler (1)
- Honey bees (1)
- Hymenopteren (1)
- Leaf cutting ants (1)
- Megaponera analis (1)
- Metarhizium anisopliae (1)
- Muscidifurax (1)
- Nasonia (1)
- Nasonia courtship (1)
- Phenols (1)
- Pheromone (1)
- Poplars (1)
- Pteromalidae (1)
- QTL analysis (1)
- Stachellose Biene (1)
- Trees (1)
- Trichomalopsis (1)
- Vicia faba (L.) (1)
- Volatile Organic Compound (VOC) (1)
- Waldökosystem (1)
- action potentials (1)
- alkaloids (1)
- alkyloctahydronaphthalene (1)
- altitudinal gradient (1)
- amphibian skin secretions (1)
- animal behaviour (1)
- antimicrobial peptides (1)
- anurans (1)
- appeasement substance (1)
- assortative mating (1)
- beta diversity (1)
- beta-multifunctionality (1)
- bumblebees (1)
- carbon dioxide (CO2) (1)
- chemical ecology (1)
- chemische Kommunikation (1)
- chemotypes (1)
- chrysididae (1)
- climatic factors (1)
- collections (1)
- conservation (1)
- crematogaster (1)
- cuticular chemistry (1)
- cuticular hydrocarbon (1)
- dendrobates pumilio (1)
- desiccation (1)
- desiccation resistance (1)
- distribution (1)
- division of labor (1)
- drought stress (1)
- dry-mounted samples (1)
- elevational gradient (1)
- entomology (1)
- environmental association (1)
- environmental association analysis (1)
- evolutionary arms race (1)
- female choice (1)
- flowering plants (1)
- flowers (1)
- insect collection (1)
- instinct (1)
- integrative taxonomy (1)
- interspecific aggression (1)
- kutikuläre Kohlenwasserstoffe (1)
- mate recognition (1)
- microbial ecology (1)
- microbiome metabarcoding (1)
- microhylidae (1)
- mountain (1)
- mutualism (1)
- mutualisms (1)
- nesting (1)
- nestmate recognition cues (1)
- neurons (1)
- neutral theory (1)
- niche differentiation (1)
- niche partitioning (1)
- nutrition (1)
- odorants (1)
- ozone (O3) (1)
- paltothyreus tarsatus (1)
- parabiosis (1)
- parabiotic ants (1)
- parabiotic association (1)
- parallel evolution (1)
- parasitism (1)
- pheromone (1)
- philanthidae (1)
- plant physiology (1)
- plant-herbivore interactions (1)
- pollen metabarcoding (1)
- pollination (1)
- pollinators (1)
- polyergus rufescens (1)
- population divergence (1)
- population structure (1)
- prezygotic reproductive isolation (1)
- principal component analysis (1)
- proteomics (1)
- rescue behavior (1)
- sex pheromone (1)
- sex pheromones (1)
- sexual dimorphism (1)
- sexual selection (1)
- species coexistence mechanism (1)
- trade‐offs (1)
- translocation experiment (1)
- usurpation (1)
- venom (1)
- zoology (1)
Institut
Sonstige beteiligte Institutionen
EU-Projektnummer / Contract (GA) number
- 741491 (1)
Insect brood parasites have evolved a variety of strategies to avoid being detected by their hosts. Few previous studies on cuckoo wasps (Hymenoptera: Chrysididae), which are natural enemies of solitary wasps and bees, have shown that chemical mimicry, i.e., the biosynthesis of cuticular hydrocarbons (CHC) that match the host profile, evolved in several species. However, mimicry was not detected in all investigated host-parasite pairs. The effect of host range as a second factor that may play a role in evolution of mimicry has been neglected, since all previous studies were carried out on host specialists and at nesting sites where only one host species occurred. Here we studied the cuckoo wasp Parnopes grandior, which attacks many digger wasp species of the genus Bembix (Hymenoptera: Crabronidae). Given its weak host specialization, P. grandior may either locally adapt by increasing mimicry precision to only one of the sympatric hosts or it may evolve chemical insignificance by reducing the CHC profile complexity and/or CHCs amounts. At a study site harbouring three host species, we found evidence for a weak but appreciable chemical deception strategy in P. grandior. Indeed, the CHC profile of P. grandior was more similar to all sympatric Bembix species than to a non-host wasp species belonging to the same tribe as Bembix. Furthermore, P. grandior CHC profile was equally distant to all the hosts' CHC profiles, thus not pointing towards local adaptation of the CHC profile to one of the hosts' profile. We conducted behavioural assays suggesting that such weak mimicry is sufficient to reduce host aggression, even in absence of an insignificance strategy, which was not detected. Hence, we finally concluded that host range may indeed play a role in shaping the level of chemical mimicry in cuckoo wasps.
Whereas interspecific associations receive considerable attention in evolutionary, behavioural and ecological literature, the proximate bases for these associations are usually unknown. This in particular applies to associations between vertebrates with invertebrates. The West-African savanna frog Phrynomantis microps lives in the underground nest of ponerine ants (Paltothyreus tarsatus). The ants usually react highly aggressively when disturbed by fiercely stinging, but the frog is not attacked and lives unharmed among the ants. Herein we examined the proximate mechanisms for this unusual association. Experiments with termites and mealworms covered with the skin secretion of the frog revealed that specific chemical compounds seem to prevent the ants from stinging. By HPLC-fractionation of an aqueous solution of the frogs' skin secretion, two peptides of 1,029 and 1,143 Da were isolated and found to inhibit the aggressive behaviour of the ants. By de novo sequencing using tandem mass spectrometry, the amino acid sequence of both peptides consisting of a chain of 9 and 11 residues, respectively, was elucidated. Both peptides were synthesized and tested, and exhibited the same inhibitory properties as the original frog secretions. These novel peptides most likely act as an appeasement allomone and may serve as models for taming insect aggression.
Insects exhibit complex systems of communication with chemical signalling being the most important mode. Although there are many studies on chemical communication in insects, the evolution of chemical signals is not well understood. Due to the conflict of interests between individuals, different selective pressures might act on sender and receiver. In this thesis I investigate different types of communication where either the sender, the receiver or both parties yield benefits. These studies were conducted with one digger wasp species, honeybees, one chrysidid wasp, and three ant species. Senders might benefit by exploiting existing preferences of receivers. Such sensory exploitation might influence the evolution of male signals that are designed to attract females. The sex pheromone of male European beewolves Philanthus triangulum (Hymenoptera, Crabronidae) might have evolved according to the sensory exploitation hypothesis. A three-step scenario is supported by our studies. First, a major component of the honeybee alarm pheromone, (Z)-11-eicosen-1-ol, is also found on the cuticles and in the air surrounding foraging honeybees. Second, it could be shown, that (Z)-11- eicosen-1-ol plays a crucial role as kairomone for prey identification of honeybees by beewolf females. Third, a reanalysis of the beewolf male sex pheromone shows a remarkable similarity of compounds between the pheromone and the honeybee cuticle, besides the co-occurrence of (Z)-11-eisosen-ol. The majority of the cuticular hydrocarbons of honeybees occur also in the headspace of foraging workers. These results strongly support the hypothesis that beewolf males evolved a pheromone that exploits the females’ pre-existing sensory sensitivity. In addition, the male sex pheromone shows a significantly higher similarity among brothers than among non-related individuals, which might enable beewolf females to discriminate against brothers and avoid detrimental effects of breeding. Together with the studies on the possible sensory exploitation this result shows that both, male and female beewolves probably gain more benefits than costs from the pheromone communication and, thus, the communication system as a whole can be regarded as cooperative. To maintain the reproductive division of labour in eusocial colonies, queens have to signal their presence and fecundity. In the ant Camponotus floridanus (Hymenoptera, Formicidae) queens mark their own eggs with a distinctive pattern of cuticular hydrocarbons. Two different hypotheses have been developed. One suggests a form of worker manipulation by the queen. The alternative hypothesis assumes a cooperative signal that provides information on the condition of the queen. The results of our investigation clearly favour the latter hypothesis. Chemical mimicry is a form of non-cooperative communication that benefits predominantly the sender. We provided conclusive evidence that the cockoo wasp, Hedychrum rutilans (Hymenoptera, Chrysididae), the primary brood parasitoid of Philanthus triangulum, evades recognition by beewolf females most probably by chemical mimicry of the odour of its host. Furthermore, the adaptation of the chemical signature in the social ant parasite Protomognathus americanus (Hymenoptera, Formicidae) to its Leptothorax (Hymenoptera, Formicidae) hosts was investigated. Although this parasite is principally adapted to its hosts’ cuticular hydrocarbon profile, there are still pronounced differences between the profiles of parasites and hosts. This might be explained by the trade-off, which the parasites faces when confronted locally with two host species with different cuticular hydrocarbon profiles. Non-cooperative communication in the sense that only receivers benefit was discovered in the exploitation of honeybees volatile cuticular hydrocarbons by beewolf females. By using emitted (Z)-11-eicosen-1-ol as a kairomone, the receiver, the beewolf female, yields the benefits and the sender, the honeybee prey, bears all the costs. The results of these studies contribute to the understanding of the evolution of cooperative and non-cooperative communication with chemical signals taking into account differential benefits for sender and/or receiver.
1. The potential for competition is highest among species in close association. Despite net benefits for both parties, mutualisms can involve costs, including food competition. This might be true for the two neotropical ants Camponotus femoratus and Crematogaster levior, which share the same nest in a presumably mutualistic association (parabiosis).
2. While each nest involves one Crematogaster and one Camponotus partner, both taxa were recently found to comprise two cryptic species that show no partner preferences and seem ecologically similar. Since these cryptic species often occur in close sympatry, they might need to partition their niches to avoid competitive exclusion.
3. Here, we investigated first, is there interference competition between parabiotic Camponotus and Crematogaster, and do they prefer different food sources under competition? And second, is there trophic niche partitioning between the cryptic species of either genus?
4. Using cafeteria experiments, neutral lipid fatty acid and stable isotope analyses, we found evidence for interference competition, but also trophic niche partitioning between Camponotus and Crematogaster. Both preferred protein‐ and carbohydrate‐rich baits, but at protein‐rich baits Ca. femoratus displaced Cr. levior over time, suggesting a potential discovery‐dominance trade‐off between parabiotic partners. Only limited evidence was found for trophic differentiation between the cryptic species of each genus.
5. Although we cannot exclude differentiation in other niche dimensions, we argue that neutral dynamics might mediate the coexistence of cryptic species. This model system is highly suitable for further studies of the maintenance of species diversity and the role of mutualisms in promoting species coexistence.
The East Himalaya is one of the world’s most biodiverse ecosystems. However, very little is known about the abundance and distribution of many plant and animal taxa in this region. Bumble bees are a group of cold-adapted and high elevation insects that fulfil an important ecological and economical function as pollinators of wild and agricultural flowering plants and crops. The Himalayan mountain range provides ample suitable habitats for bumble bees. Systematic study of Himalayan bumble bees began a few decades ago and the main focus has centred on the western region, while the eastern part of the mountain range has received little attention and only a few species have been verified. During a three-year survey, more than 700 bumble bee specimens of 21 species were collected in Arunachal Pradesh, the largest of the north-eastern states of India. The material included a range of species that were previously known from a limited number of collected specimens, which highlights the unique character of the East Himalayan ecosystem. Our results are an important first step towards a future assessment of species distribution, threat, and conservation. Clear elevation patterns of species diversity were observed, which raise important questions about the functional adaptations that allow bumble bees to thrive in this particularly moist region in the East Himalaya.
To trigger innate behavior, sensory neural networks are pre-tuned to extract biologically relevant stimuli. Many male-female or insect-plant interactions depend on this phenomenon. Especially communication among individuals within social groups depends on innate behaviors. One example is the efficient recruitment of nest mates by successful bumblebee foragers. Returning foragers release a recruitment pheromone in the nest while they perform a ‘dance’ behavior to activate unemployed nest mates. A major component of this pheromone is the sesquiterpenoid farnesol. How farnesol is processed and perceived by the olfactory system, has not yet been identified. It is much likely that processing farnesol involves an innate mechanism for the extraction of relevant information to trigger a fast and reliable behavioral response. To test this hypothesis, we used population response analyses of 100 antennal lobe (AL) neurons recorded in alive bumblebee workers under repeated stimulation with four behaviorally different, but chemically related odorants (geraniol, citronellol, citronellal and farnesol). The analysis identified a unique neural representation of the recruitment pheromone component compared to the other odorants that are predominantly emitted by flowers. The farnesol induced population activity in the AL allowed a reliable separation of farnesol from all other chemically related odor stimuli we tested. We conclude that the farnesol induced population activity may reflect a predetermined representation within the AL-neural network allowing efficient and fast extraction of a behaviorally relevant stimulus. Furthermore, the results show that population response analyses of multiple single AL-units may provide a powerful tool to identify distinct representations of behaviorally relevant odors.