Mandibular Gland Volatiles and Their Ontogenetic Patterns in Queen Honey Bees,Apis mellifera carnica

Extracts of mandibular glands taken from adult queens of the honey bee, Apis mellifera carnica, were analysed by gas chromatography-mass spectroscopy. More than 100 compounds could be identified among which oxygenated fatty acids with six, eight, 10 and 12 carbon atoms are particularly interesting since they show structural relationships to the queen substance, (E)-9-oxo-2-decenoic acid. Changes in the patterns of volatiles were followed up from emergence until the full dominant status of an egg-laying queen in a strong colony. Generally, the amount of volatiles per gland was found to increase with age. The final level of queen substance (9-ODA) content is reached at the postmating stage about 10 days after emergence. Ontogenetic patterns of concentrations were determined for those components regarded to predominantly contribute to the royal pheromone. Characteristic compositions of signals, possibly involved in the premating, mating and postmating dominance status of a honey bee queen are discussed. Copyright 1997 Elsevier Science Ltd. All rights reserved     

The Behavior of Communicating: An Analysis of the 22 kHz Call of Rats (Rattus Norvegicus)

The 22 kHz vocalization of male rats (R. norvegicus) occursin a wide variety of social contexts. It is, for example, emittedduring sexual and aggressive encounters. In this anicle, weput forth the idea that although the specific meaning of thesignal varies from one social situation to another, the messageis similar–the animal is in a refractory, withdrawn, orhelpless state. To demonstrate that the signal produced in one behavioral contextcould function appropriately in another, we showed that a malerat, emitting the 22 kHz call because of just having copulated,is treated by an aggressive male as if he were submissive. Tohighlight the communality between the refractory states of thevocalizing animal in various social contexts, we demonstratedthat a postejaculatory male (during the time that he would becalling) behaves in a fashion similar to that of an animal thatis in a state of learned helplessness.     

Influence of leaf herbivory,root herbivory,and pollination on plant performance in Cucurbita moschata

Abstract 1. Plants experience herbivory on many different tissues that can affect reproduction directly by damaging tissues and decreasing resource availability, or indirectly via interactions with other species such as pollinators. 2. This study investigated the combined effects of leaf herbivory, root herbivory, and pollination on subsequent damage, pollinator preference, and plant performance in a field experiment using butternut squash (Cucurbita moschata). Leaf and root herbivory were manipulated using adult and larval striped cucumber beetles (Acalymma vittatum F.), a cucurbit specialist. 3. Leaf herbivory reduced subsequent pistillate floral damage and powdery mildew (Sphaerotheca fuliginea) infection. In spite of these induced defences, the overall effect of leaf herbivory on plant reproduction was negative. Leaf herbivory reduced staminate flower production, fruit number, and seed weight. In contrast, root herbivory had a minimal impact on plant reproduction. 4. Neither leaf nor root herbivory altered pollinator visitation or floral traits, suggesting that reductions in plant performance from herbivory were as a result of direct rather than indirect effects. In addition, no measured aspect of reproduction was pollen limited. 5. Our study reveals that although leaf herbivory by the striped cucumber beetle can protect against subsequent damage, this protection was not enough to prevent the negative impacts on plant performance.     

The Simulium vernum group (Diptera: Simuliidae) in Europe: multiple character sets for assessing species status

The value of using characters from multiple sources – chromosomes, ecology, gene sequences, and morphology – to evaluate the species status of closely related black flies is demonstrated for three European members of the Simulium vernum group: Simulium crenobium (Knoz, 1961), Simulium juxtacrenobium Bass & Brockhouse, 1990, and Simulium vernum s.s. Macquart, 1826. Simulium juxtacrenobium is a chromosomally, molecularly, and morphologically distinct species that diverged from S. crenobium and S. vernum s.s. about 2 Mya. It is specialized for intermittent streams, is univoltine, and is recorded for the first time from northern Europe, based on collections from Finland and Sweden, representing a range extension of about 1800 km. In contrast, S. crenobium, although confirmed as a distinct species, differs from S. vernum s.s. by only a few larval and chromosomal characters, and by a breeding habitat restricted to mountain spring brooks. Whereas all four character sets independently support the specific distinctness of S. juxtacrenobium and S. vernum s.s., multiple character sets are required to establish the specific validity of S. crenobium.     

Cytosystematics of the Simulium tuberosum group (Diptera: Simuliidae) in Thailand

The polytene chromosomes of 3347 larvae of the Simulium tuberosum group in Asia were analysed, representing the largest ever cytogenetic study of black flies in the Oriental Region. Band‐by‐band comparisons, relative to the established standard chromosome map for the subgenus Simulium, revealed 17 cytogenetically distinct taxa in Thailand, plus an 18th in China. Six of these taxa correspond to morphologically described species (S. doipuiense, S. rufibasis, S. setsukoae, S. tani, S. yuphae and S. weji). Recognition of the 18 taxa is based largely on unique inversions, either fixed or sex linked, primarily in the long arm of chromosome III. The greatest cytological diversity was discovered in the S. tani lineage, with ten cytoforms. This marked chromosomal diversification within S. tani is based largely on two inversions that have assumed different roles over evolutionary time, variously functioning in different combinations as fixed inversions, sex‐linked inversions and autosomal polymorphisms. Shared unique chromosomal features, relative to the subgeneric standard chromosome map, allowed evolutionary relationships among the cytotaxa to be inferred. Fluctuations in climate during the Pleistocene might have promoted differentiation of the Southeast Asian S. tuberosum group in isolated refugia such as mountains. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 289–315.