Ant queens (Hymenoptera: Formicidae) are attracted to fungal pathogens during the initial stage of colony founding

Ant queens that attempt to disperse and found new colonies independently face high mortality risks. The exposure of queens to soil entomopathogens during claustral colony founding may be particularly harmful, as founding queens lack the protection conferred by mature colonies. Here, we tested the hypotheses that founding queens (I) detect and avoid nest sites that are contaminated by fungal pathogens, and (II) tend to associate with other queens to benefit from social immunity when nest sites are contaminated. Surprisingly, in nest choice assays, young Formica selysi BONDROIT, 1918 queens had an initial preference for nest sites contaminated by two common soil entomopathogenic fungi, Beauveria bassiana and Metarhizium brunneum. Founding queens showed a similar preference for the related but non-entomopathogenic fungus Fusarium graminearum. In contrast, founding queens had no significant preference for the more distantly related nonentomopathogenic fungus Petromyces alliaceus, nor for heat-killed spores of B. bassiana. Finally, founding queens did not increase the rate of queen association in presence of B. bassiana. The surprising preference of founding queens for nest sites contaminated by live entomopathogenic fungi suggests that parasites manipulate their hosts or that the presence of specific fungi is a cue associated with suitable nesting sites.

Effects of brood manipulation costs on optimal sex allocation in social hymenoptera.

In eusocial Hymenoptera, queens and workers are in conflict over optimal sex allocation. Sex ratio theory, while generating predictions on the extent of this conflict under a wide range of conditions, has largely neglected the fact that worker control of investment almost certainly requires the manipulation of brood sex ratio. This manipulation is likely to incur costs, for example, if workers eliminate male larvae or rear more females as sexuals rather than workers. In this article, we present a model of sex ratio evolution under worker control that incorporates costs of brood manipulation. We assume cost to be a continuous, increasing function of the magnitude of sex ratio manipulation. We demonstrate that costs counterselect sex ratio biasing, which leads to less female-biased population sex ratios than expected on the basis of relatedness asymmetry. Furthermore, differently shaped cost functions lead to different equilibria of manipulation at the colony level. While linear and accelerating cost functions generate monomorphic equilibria, decelerating costs lead to a process of evolutionary branching and hence split sex ratios.

Contribution à la biologie de Tapinoma melanocephalum (Fabricius) (Hymenoptera: Formicidae)

Under laboratory conditions it has been possible to show that Tapinoma melanocephalum could be considered as a tramp species. Functionnal polygyny, unicoloniality and budding are investigated.

Allergie aux venins d'hyménopteres: nouveautés diagnostiques et prise en charge [Hymenoptera venom allergy: new diagnostic tools and management].

Anaphylactic reactions to hymenoptera venoms are common and, in our latitudes, mainly concern wasps and bees. Recently, molecular biology techniques have contributed to identifying and to sequencing the major allergens of insect venoms and led to the production of recombinant allergens. Assays for specific IgE directed against these recombinant allergens have recently been made available in clinical practice. They provide considerable assistance in identifying the insect responsible for an anaphylactic reaction, in particular when standard tests are positive for both wasp and bee. This article focuses on these new laboratory tests and also reviews the management of patients experiencing an anaphylactic reaction after hymenoptera sting.

Between-year variation in population sex ratio increases with complexity of the breeding system in Hymenoptera.

While adaptive adjustment of sex ratio in the function of colony kin structure and food availability commonly occurs in social Hymenoptera, long-term studies have revealed substantial unexplained between-year variation in sex ratio at the population level. In order to identify factors that contribute to increased between-year variation in population sex ratio, we conducted a comparative analysis across 47 Hymenoptera species differing in their breeding system. We found that between-year variation in population sex ratio steadily increased as one moved from solitary species, to primitively eusocial species, to single-queen eusocial species, to multiple-queen eusocial species. Specifically, between-year variation in population sex ratio was low (6.6% of total possible variation) in solitary species, which is consistent with the view that in solitary species, sex ratio can vary only in response to fluctuations in ecological factors such as food availability. In contrast, we found significantly higher (19.5%) between-year variation in population sex ratio in multiple-queen eusocial species, which supports the view that in these species, sex ratio can also fluctuate in response to temporal changes in social factors such as queen number and queen-worker control over sex ratio, as well as factors influencing caste determination. The simultaneous adjustment of sex ratio in response to temporal fluctuations in ecological and social factors seems to preclude the existence of a single sex ratio optimum. The absence of such an optimum may reflect an additional cost associated with the evolution of complex breeding systems in Hymenoptera societies.

Tapinoma pygmaeum (Dufour, 1857) (Hymenoptera, Formicidae), not a rare species

Tapinoma pygmaeum is an ant known from seven localities. Five of them are in theprovince of Girona (Spain). The apparent rarity and skewed distribution of this species isprobably an artifact due to the confussion, in field samplings, with a similar speciesPlagiolepis pygmaea

Description of a new artificial diet for rearing ant colonies as Iridomyrmex humilis, Monomorium pharaonis and Wasmannia auropunctata (Hymenoptera, Formicidae)

A diet which does not desiccate was developed for rearing various ant species. this diet was found to be very attractive forIridomyrmex humilis. Monomorium pharaonis andWasmannia auropunctata in which species it permitted the rearing of colonies for long periods and the regular production of sexuals. Nous présentons la recette d'une nourriture artificielle élaborée pour élever des fourmis en laboratoire. Cette nourriture ne se dessèche pas et s'est avérée adéquate pour l'élevage de plusieur espèces telles queIridomyrmex humilis, Monomorium pharaonis etWasmannia auropunctata. Des sexués mâles et femelles ont été régulièrement produits dans ces sociétés.

Introduced ant species and mechanisms of competition on Floreana Island (Galapagos, Ecuador) (Hymenoptera : Formicidae)

Simultaneous presence of several tramp ant species of relatively recent introduction on a remote island is an excellent opportunity to study competition mechanisms that lead to the establishment of invasive species. Using attractive food baits we collected 14 ant species among which 10 are well-known tramp species. The most important change between 1996-97 and 2003 is the spread of the tropical fire ant Solenopsis geminata at the detriment of Tetramorium simillimum, suggesting that the colonization process on Floreana is still very dynamic. The follow-up of 400 food baits for 21 hours permitted us to calculate indices of competition abilities for 11 species, revealing distinct strategies. The two small tramp species Monomorium floricola and Tapinoma melanocephalum are typically opportunists when large-sized Odontomachus bauri (possibly native species) and Camponotus macilentus (endemic species) are good interference competitors, out-competing other species at food baits. Dominant species S. geminata and Monomorium destructor reach high scores for all indices due to their high abundance.

Molecular taxonomy of the Formica rufa group (red wood ants) (Hymenoptera: Formicidae): a new cryptic species in the Swiss Alps?

Because of their beneficial impact on forest ecosystems, European red wood ants (Formica rufa group) are protected by law in many European countries and are considered to be among the most reliable bioindicators of forest stability. However, their taxonomy has been much debated and, unfortunately, it is too often neglected. This happens mainly because the morphology-based method for species delimitation requires lots of time and experience. We therefore employed 9 microsatellite loci and mitochondrial DNA (COI gene) to verify the power of genetic markers for red wood ant species delimitation and to investigate the cryptic diversity of these ants within the Eastern Swiss Alps. We analyzed 83 nests belonging to all red wood ant species that occur in the Swiss National Park area. Genetic data indicated that these species represent different genetic pools. Moreover, results showed that Formica aquilonia YARROW, 1955 and F. paralugubris SEIFERT, 1996 often hybridize within the Park, confirming that these two species are genetically very close and could have diverged only recently. Nevertheless, microsatellites also revealed that one entire population, located in the Minger Valley and morphologically identified as F. lugubris ZETTERSTEDT, 1838, is genetically different to all other analyzed F. lugubris populations found within the same area and to other red wood ant species. These findings, confirmed by mitochondrial DNA analyses, suggest the existence of a new cryptic species within the Eastern Swiss Alps. This putative cryptic species has been provisionally named F. lugubris-A2. These results have a great importance for future conservation plans, monitoring and evolutionary studies on these protected ants.

Estudio comparativo de las estructuras genitales del macho en el género Pseudocentron (Hymenoptera, Megachilidae)

Comparative study of the structures of male genitalia in Pseudocentron species (Hymenoptera, Megachilidae). Male genitalia of twenty two species of Pseudocentron Mitchell, 1934 belonging to seven subgenera are analysed. The diagnostic characters are described and illustrated. The study shows that the male genitalia provides diagnostic characters at generic, subgeneric and specific levels.

New species of Apenesia (Hymenoptera, Bethylidae) from the Parque Nacional da Serra do Divisor, Acre, Brazil

Ten new species of Apenesia Westwood, 1874, from Brazil, Acre, are described and illustrated. They belong, respectively, to the following species-groups: nitida group, Apenesia lobata sp. nov., A. serrulata sp. nov. and A. subangulata sp. nov.; laevigata group, A. ocullata sp. nov. and A. rostrum sp. nov.; columbana group, A. apicilata sp. nov.; mexicana group, A. triapicalis sp. nov.; brasiliensis group, A. megaventris sp. nov., A. ventosa sp. nov. and A. triangula sp. nov. New geographical records and some morphological data on A. funebris Evans, 1963, A. nitida (Kieffer, 1910) and A. truncaticeps (Kieffer, 1910) are added.

Systematics of Epyris (Hymenoptera, Bethylidae) from reserva biológica de duas bocas, Espírito Santo, Brazil

Epyris longus sp. nov., Epyris paramedius sp. nov., Epyris distinctus sp. nov. and Epyris variatus sp. nov. from Reserva Biológica de Duas Bocas, Espírito Santo, Brazil are described and illustrated. Examination of additional specimens of Epyris crassifemur Evans, 1969 allowed to analyse the intraspecific variation as well as to widen the geographic distribution from Santa Catarina to Espírito Santo. Epyris Westwood, 1832 is recorded for the first time in Espírito Santo.

Perfil da fauna de himenópteros parasitóides (Insecta, Hymenoptera) em uma área de Mata Atlântica do Parque Estadual da Fonte Grande, Vitória, ES, Brasil

Survey of the hymenopterous parasitoids (Insecta, Hymenoptera) from the Parque Estadual da Fonte Grande, Vitória, ES, Brazil. Parasitoids Hymenoptera were collected in a trail inside the Parque Estadual da Fonte Grande (20º17'51.7''S; 40º20'13.1''W), located in an area of the Atlantic Forest, during the period of June 2000 to July 2001. A total of 4,595 specimens, belonging to 28 families, have been collected. Braconidae, Eulophidae, and Scelionidae, were the most common families, with relative abundance of 22.5%, 14.32%, and 13.12%, respectively. Sixteen families showed the relative frequency lower than 1%. A preliminary list with 47 genera of some of the families is included.

Himenópteros parasitóides (Insecta, Hymenoptera) coletados em cultura de algodão (Gossypium hirsutum L.) (Malvaceae), no município de Ribeirão Preto, SP, Brasil

Parasitoid Hymenoptera (Insecta, Hymenoptera) collected in a cotton (Gossypium hirsutum L.) (Malvaceae) plantation at the municipal district of Ribeirão Preto, SP, Brazil. Parasitoid Hymenoptera were collected by using Moericke trap placed in a cotton plantation (Gossypium hirsutum L.) of the variety Delta Pine 90, during the period of February 23rd to April 3rd, 2001. A total of 16,166 specimens of parasitoids, belonging to eight superfamilies and 22 families, were collected. Encyrtidae, Trichogrammatidae, Mymaridae and Scelionidae were the most common families, being responsible for 45.14%, 19.11%, 14.33% and 6.57% of the total number of parasitoids collected, respectively. Other eigthteen families showed the relative frequency lower than 5%.

Himenópteros parasitóides (Insecta, Hymenoptera) coletados em cultura de soja (Glycine max (L.)) Merril (Fabaceae), no município de Nuporanga, SP, Brasil

Parasitoid Hymenoptera collected in a soybean plantation (Glycine max (L.)) Merril (Fabaceae) at the municipal district of Nuporanga, SP, Brazil. Parasitoid Hymenoptera were collected by using Moericke trap placed in a soybean plantation (Glycine max (L.) Merril) (Fabaceae) of the variety Conquista, during the period of March 24th to April 7th, 2000. A total of 4,969 specimens of parasitoids, belonging to seven superfamilies and 15 families, were collected. Scelionidae, Encyrtidae, Aphelinidae and Trichogrammatidae were the most common families, being responsible for 41.66%, 19.42%, 11.19% and 7.35% of the total number of parasitoids collected, respectively. Other eleven families showed the relative frequency lower than 5%.