Host-parasitoid interactions between the solitary bee Centris analis (Apidae: Centridini) and conopid flies (Diptera: Conopidae).

Natural enemies are one of the main mortality factors in bees and wasps attacking either immature stages or adults of their hosts. Dipterans of the genus Physocephala (Diptera: Conopidae) are parasitoids that attack adult bees during their field activities, and the parasitoid larvae develop inside the host abdomen. However, little is known about the biology of these natural enemies and their interactions with their solitary bee hosts. This study is aimed at analyzing attacks by conopid flies in one of their hosts, the solitary bee species Centris analis (Apidae: Centridini), and the consequences in the nesting behavior of this bee species. Higher incidences of parasitism occurred during the hot/wet season, and seven fly species attacking C. analis were identified. Of the fifty-six females observed during their nesting activities, seven of them were parasitized. These females showed alterations in their nesting behavior, depositing extra oil on the plug of finished nests and building plugs in empty cavities. The behavioral changes observed in these females began during larval stage L1 of the parasitoid. In the last stages of parasitoid development (L3 PUP and pupa), the bees ceased their flight activities and entered cavities at the nesting site, remaining there until death.

Warming and elevated CO2 induces changes in the reproductive dynamics of a tropical plant species.

Tropical plant species are vulnerable to climate change and global warming. Since flowering is a critical factor for plant reproduction and seed-set, warming and elevated atmospheric carbon dioxide concentrations (eCO2) are crucial climate change factors that can affect plant reproductive dynamics and flowering related events in the tropics. Using a combined free-air CO2 enrichment and a free-air temperature-controlled enhancement system, we investigate how warming (+2 °C above ambient, eT) and elevated [CO2] (~600 ppm, eCO2) affect the phenological pattern, plant-insect interactions, and outcrossing rates in the tropical legume forage species Stylosanthes capitata Vogel (Fabaceae). In comparison to the control, a significantly greater number of flowers (NF) per plot (+62%) were observed in eT. Furthermore, in warmed plots flowers began opening approximately 1 h earlier (~09:05), with a canopy temperature of ~23 °C, than the control (~09:59) and eCO2 (~09:55) treatments. Flower closure occurred about 3 h later in eT (~11:57) and control (~13:13), with a canopy temperature of ~27 °C. These changes in flower phenology increased the availability of floral resources and attractiveness for pollinators such as Apis mellifera L. and visitors such as Paratrigona lineata L., with significant interactions between eT treatments and insect visitation per hour/day, especially between 09:00-10:40. In comparison to the control, the additive effects of combined eCO2 + eT enhanced the NF by 137%, while the number of A. mellifera floral visits per plot/week increased by 83% during the period of greatest flower production. Although we found no significant effect of treatments on mating system parameters, the overall mean multilocus outcrossing rate (tm = 0.53 ± 0.03) did confirm that S. capitata has a mixed mating system. The effects of elevated [CO2] and warming on plant-pollinator relationships observed here may have important implications for seed production of tropical forage species in future climate scenarios.

Exploring integument transcriptomes, cuticle ultrastructure, and cuticular hydrocarbons profiles in eusocial and solitary bee species displaying heterochronic adult cuticle maturation.

Differences in the timing of exoskeleton melanization and sclerotization are evident when comparing eusocial and solitary bees. This cuticular maturation heterochrony may be associated with life style, considering that eusocial bees remain protected inside the nest for many days after emergence, while the solitary bees immediately start outside activities. To address this issue, we characterized gene expression using large-scale RNA sequencing (RNA-seq), and quantified cuticular hydrocarbon (CHC) through gas chromatography-mass spectrometry in comparative studies of the integument (cuticle plus its underlying epidermis) of two eusocial and a solitary bee species. In addition, we used transmission electron microscopy (TEM) for studying the developing cuticle of these and other three bee species also differing in life style. We found 13,200, 55,209 and 30,161 transcript types in the integument of the eusocial Apis mellifera and Frieseomelitta varia, and the solitary Centris analis, respectively. In general, structural cuticle proteins and chitin-related genes were upregulated in pharate-adults and newly-emerged bees whereas transcripts for odorant binding proteins, cytochrome P450 and antioxidant proteins were overrepresented in foragers. Consistent with our hypothesis, a distance correlation analysis based on the differentially expressed genes suggested delayed cuticle maturation in A. mellifera in comparison to the solitary bee. However, this was not confirmed in the comparison with F. varia. The expression profiles of 27 of 119 genes displaying functional attributes related to cuticle formation/differentiation were positively correlated between A. mellifera and F. varia, and negatively or non-correlated with C. analis, suggesting roles in cuticular maturation heterochrony. However, we also found transcript profiles positively correlated between each one of the eusocial species and C. analis. Gene co-expression networks greatly differed between the bee species, but we identified common gene interactions exclusively between the eusocial species. Except for F. varia, the TEM analysis is consistent with cuticle development timing adapted to the social or solitary life style. In support to our hypothesis, the absolute quantities of n-alkanes and unsaturated CHCs were significantly higher in foragers than in the earlier developmental phases of the eusocial bees, but did not discriminate newly-emerged from foragers in C. analis. By highlighting differences in integument gene expression, cuticle ultrastructure, and CHC profiles between eusocial and solitary bees, our data provided insights into the process of heterochronic cuticle maturation associated to the way of life.

Nesting behavior of Podium denticulatum Smith (Hymenoptera: Sphecidae).

The nesting behavior of Podium denticulatum Smith was studied on the campus of Ribeirão Preto of the Universidade de São Paulo, SP, Brazil, from September 2003 to August 2005. The wasps established their nests in bamboo canes ranging from 11.4 cm to 26.2 cm in length and from 0.7 cm to 1.8 cm in internal diameter. Podium denticulatum nested almost exclusively in the hot and wet season (September-April), producing at least five generations per year. The cell provisioning was made with adult and nymphal cockroaches (Blattellidae) which were arranged venter-up and with the head inward toward the inner end of the cell. The construction of a temporary closure occurred in cells that took more than one day to be provisioned. The cells provisioned with a greater number of prey were more likely to produce females than males. The nests included 1-6 brood cells separated by mud partitions and arranged in a linear series. The innermost cells of the nests produced females, and the outermost cells produced males. Nests were parasitized by Eulophidae (Melittobia sp.), Chrysididae and Tachinidae.

Conopid flies (Diptera: Conopidae) parasitizing Centris (Heterocentris) analis (Fabricius) (Hymenoptera: Apidae, Centridini).

Parasites of adult bees are almost exclusively flies and the most important of them are conopids. This note registers for the first time the association of species of Physocephala (Diptera: Conopidae) with Centris (Heterocentris) analis (Fabricius). From 26 females and nine males of the host species found dead inside trap-nests on the campus of the University of São Paulo, Ribeirão Preto, Brazil, 35 parasitoids were obtained belonging to nine species of Physocephala. The data show that C. analis is a host to several conopid flies, and suggest that such parasitoids can play an important role in population control of this bee species.

[Nesting of Euglossa (Euglossa) melanotricha Moure (Hymenoptera: Apidae) in the ground of cerrado]. / Nidificação de Euglossa (Euglossa) melanotricha Moure (Hymenoptera: Apidae) no solo do cerrado.

Nests of euglossine bees are difficult to found in nature, with descriptions available for only 20% of known species. A nest of Euglossa (Euglossa) melanotricha Moure found inside a cavity in the ground at a Cerrado area in Uberlândia, Minas Gerais state, is described. Comparisons of nesting behavior and social structure with those reported for Euglossa (Euglossa) cordata (L.) and Euglossa (Euglossa) townsendi Cokerell are presented and discussed.

Small-scale elevational variation in the abundance of Eufriesea violacea (Blanchard) (Hymenoptera: Apidae).

Eufriesea violacea (Blanchard) males were sampled in a small-scale elevational gradient in Southeastern Brazil and showed sequential peaks of abundance from lowest (700 m) to highest (1,100 m) altitudes during the sampling period. The influence of the temperature on the length of the egg-to-adult period and flowering dates of plants producing food (nectar) suggests that it may be one of the factors determining the distribution of male abundance along the altitudinal gradient. The results emphasize the importance of obtaining altitudinal stratified samples when studying Euglossini populations, especially when the studies are done at sites with marked topographical variation.

Occurrence of Aglae caerulea Lepeletier & Serville (Hymenoptera: Apidae: Euglossini) in the Parque Nacional da Chapada dos Guimarães, Mato Grosso State, Brazil.

In a study conducted in the gallery forest of the Vale doVeu de Noiva in the Parque Nacional da Chapada dos Guimarães, Mato Grosso state, chemical baits were used to attract and sample male orchid bees. From September 2003 to July 2005, male euglossine bees were captured monthly, from 8:00 a.m. to 4:00 p.m. as they arrived at the baits. Of the 264 males captured, eight males belonged to Aglae caerulea Lepeletier & Serville, a cleptoparasitic euglossine species that presumably occurred only in the Amazon basin. Therefore, the occurrence of A. caerulea in this study area extends its geographical distribution range by approximately 2,400 km southwards in South America, as it is now recorded in both the Amazon and Platina basins.

Nesting behavior of Podium denticulatum Smith (Hymenoptera: Sphecidae)

The nesting behavior of Podium denticulatum Smith was studied on the campus of Ribeirão Preto of the Universidade de São Paulo, SP, Brazil, from September 2003 to August 2005. The wasps established their nests in bamboo canes ranging from 11.4 cm to 26.2 cm in length and from 0.7 cm to 1.8 cm in internal diameter. Podium denticulatum nested almost exclusively in the hot and wet season (September-April), producing at least five generations per year. The cell provisioning was made with adult and nymphal cockroaches (Blattellidae) which were arranged venter-up and with the head inward toward the inner end of the cell. The construction of a temporary closure occurred in cells that took more than one day to be provisioned. The cells provisioned with a greater number of prey were more likely to produce females than males. The nests included 1-6 brood cells separated by mud partitions and arranged in a linear series. The innermost cells of the nests produced females, and the outermost cells produced males. Nests were parasitized by Eulophidae (Melittobia sp.), Chrysididae and Tachinidae.

Conopid flies (Diptera: Conopidae) parasitizing Centris (Heterocentris) analis (Fabricius) (Hymenoptera: Apidae, Centridini) / Conopídeos (Diptera: Conopidae) parasitando Centris (Heterocentris) analis (Fabricius) (Hymenoptera: Apidae, Centridini)

Parasitas de abelhas adultas são quase exclusivamente moscas e dentre os mais importantes estão os conopídeos. Nesta comunicação relata-se pela primeira vez a associação de espécies de Physocephala (Diptera: Conopidae) com Centris (Heterocentris) analis (Fabricius). De uma amostra de 26 fêmeas e nove machos da espécie hospedeira encontrados mortos em ninhos-armadilha vazios, no campus da Universidade de São Paulo, Ribeirão Preto, SP, emergiram 35 parasitóides pertencentes a nove espécies de Physocephala. Os dados mostram que C. analis é hospedeiro para várias espécies de conopídeos e sugerem que tais parasitóides podem desempenhar um papel importante na regulação populacional dessa espécie de abelha.

Parasites of adult bees are almost exclusively flies and the most important of them are conopids. This note registers for the first time the association of species of Physocephala (Diptera: Conopidae) with Centris (Heterocentris) analis (Fabricius). From 26 females and nine males of the host species found dead inside trap-nests on the campus of the University of São Paulo, Ribeirão Preto, Brazil, 35 parasitoids were obtained belonging to nine species of Physocephala. The data show that C. analis is a host to several conopid flies, and suggest that such parasitoids can play an important role in population control of this bee species.

Nidificação de Euglossa (Euglossa) melanotricha Moure (Hymenoptera: Apidae) no solo do cerrado / Nesting of Euglossa (Euglossa) melanotricha Moure (Hymenoptera: Apidae) in the ground of cerrado

Ninhos de Euglossini dificilmente são encontrados na natureza e existem informações disponíveis apenas para 20 por cento das espécies conhecidas. Um ninho de Euglossa (Euglossa) melanotricha Moure, encontrado em uma cavidade no solo em uma área de Cerrado do municipio de Uberlândia, MG, é descrito. Comparações com o comportamento de nidificação e estrutura social descritos para Euglossa (Euglossa) cordata (L.) e Euglossa (Euglossa) townsendi Cokerell são apresentadas e discutidas.

Nests of euglossine bees are difficult to found in nature, with descriptions available for only 20 percent of known species. A nest of Euglossa (Euglossa) melanotricha Moure found inside a cavity in the ground at a Cerrado area in Uberlândia, Minas Gerais state, is described. Comparisons of nesting behavior and social structure with those reported for Euglossa (Euglossa) cordata (L.) and Euglossa (Euglossa) townsendi Cokerell are presented and discussed.

Small-scale elevational variation in the abundance of Eufriesea violacea (Blanchard) (Hymenoptera: Apidae)

Eufriesea violacea (Blanchard) males were sampled in a small-scale elevational gradient in Southeastern Brazil and showed sequential peaks of abundance from lowest (700 m) to highest (1,100 m) altitudes during the sampling period. The influence of the temperature on the length of the egg-to-adult period and flowering dates of plants producing food (nectar) suggests that it may be one of the factors determining the distribution of male abundance along the altitudinal gradient. The results emphasize the importance of obtaining altitudinal stratified samples when studying Euglossini populations, especially when the studies are done at sites with marked topographical variation.

Machos de Eufriesea violacea (Blanchard) foram amostrados em um pequeno gradiente altitudinal no Sudeste do Brasil e apresentaram picos seqüenciais de abundância do ponto mais baixo (700 m) para o ponto mais alto (1.100 m) do gradiente durante o período de amostragem. A influência da temperatura sobre a duração do período de ovo-a-adulto e nas épocas de florescimento de plantas fornecedoras de alimento (néctar) sugere que esse seja um dos fatores que determinam a distribuição da abundância dos machos ao longo do gradiente altitudinal. Os resultados ressaltam a importância de se obter amostras estratificadas em função da altitude quando populações de Euglossini são estudadas, especialmente em localidades com grande variação topográfica.

Occurrence of Aglae caerulea Lepeletier & Serville (Hymenoptera: Apidae: Euglossini) in the Parque Nacional da Chapada dos Guimarães, Mato Grosso State, Brazil

In a study conducted in the gallery forest of the Vale doVeu de Noiva in the Parque Nacional da Chapada dos Guimarães, Mato Grosso state, chemical baits were used to attract and sample male orchid bees. From September 2003 to July 2005, male euglossine bees were captured monthly, from 8:00 a.m. to 4:00 p.m. as they arrived at the baits. Of the 264 males captured, eight males belonged to Aglae caerulea Lepeletier & Serville, a cleptoparasitic euglossine species that presumably occurred only in the Amazon basin. Therefore, the occurrence of A. caerulea in this study area extends its geographical distribution range by approximately 2,400 km southwards in South America, as it is now recorded in both the Amazon and Platina basins.

Em um estudo conduzido em uma floresta de galeria do Vale do Véu de Noiva no Parque Nacional da Chapada dos Guimarães, MT, substâncias puras foram utilizadas para atrair e amostrar machos das abelhas das orquídeas. De setembro de 2003 a julho de 2005, uma vez por mês, das 8:00h às 16:00h, os machos foram capturados conforme eles chegavam às iscas-odores. Dos 264 machos coletados, oito eram Aglae caerulea Lepeletier & Serville, uma espécie cleptoparasítica com distribuição geográfica restrita à Bacia Amazônica. Portanto, a ocorrência de A. caerulea naquela área de estudo amplia aproximadamente em 2.400 km os limites para o sul da América do Sul, estando agora documentada sua presença tanto na Bacia Amazônica como na Bacia Platina.