Sex ratio and parental investment in Trypoxylon (Trypargilum) agamemnon Richards (Hymenoptera, Crabronidae)

The life history and sex ratio data of the solitary wasp Trypoxylon agamemnon nesting in trap-nests in southern Brazil was recorded from January 2002 to December 2007. Its sex ratio is strongly female-biased, being bivoltine or multivoltine with until three generations per year. It has two alternative life histories (diapause and direct development) and overlapping generations. In addition to the conflict of interest between the sexes, it is possible that local mate competition occurs between males and may cause a greater investment in the production of females

Nesting behavior of Trypoxylon (Trypargilum) agamemnom Richards (Hymenoptera: Crabronidae)

Nesting behaviour is extremely diversified among solitary nesting sphecids. Thus, the aim of this study was to describe the nesting behaviour of Trypoxylon agamemnon and discuss the advantages of guarding behaviour of males. It was conducted in the Parque Municipal das Araucárias, Guarapuava (PR), Brazil from October/2003 to July/2007. To describe the behaviour of T. agamemnon and construct its ethogram, daily observations were made, totalling 410:19 hours observation. Although the males of T. agamemnon stand guard close to the entrance of the nests, we concluded that this behaviour is not ensuring the protection of nests against parasitoids and that, probably, this behaviour ensures them the paternity, but further studies with microsatellite markers will be necessary to confirm this hypothesis

Biologic aspects of different species of Pachodynerus (Hymenoptera; Vespidae; Eumeninae)

The aim of this study was to compare biological aspects of the Pachodynerus species occurring in the Parque Municipal das Araucárias, Guarapuava, Paraná, Southern Brazil. It was carried from December 2001 to December 2004. Forty one nests belonging to 5 species were collected, of which 17 Pachodynerus guadulpensis, 15 Pachodynerus sp., 1 Pachodynerus argentinus, 1 Pachodynerus ca guadulpensis and 7 Pachodynerus nasidens. The nesting activity of Pachodynerus sp., P. argentinus and P. guadulpensis occurred in similar periods, from December to March, with the exception of P.guadulpensis, that built one nest in October. Pachodynerus ca guadulpensis nested in March and P. nasidens from January to April. The nests of Pachodynerus species present a very similar architecture, comprising a linear series of cylindrical cells that fit perfectly into each other forming a continuous tube. With these results we were able to conclude that, even though Pachodynerus species present common characteristics, such as nest architecture, nesting activities and habitats in which they occur, the used resources, mortality rates, etc., vary among groups of species occurring in different regions

Nesting Biology of Podium angustifrons Kohl (Hymenoptera, Sphecidae) in an Araucaria Forest Fragment

Podium angustifrons Kohl 1902 is a species of solitary wasp which nests in pre-existing cavities, with neotropical distribution in Argentina, Bolivia, Brazil, Colombia, Guyana and French Guyana. The aim of this study was to investigate the nesting biology of P. angustifrons, discussing aspects of their life history. To capture its nests, wooden trap-nests were installed in the Parque Municipal das Araucárias, Guarapuava (PR), Brazil, from January 2003 to April 2009. A total of 29 nests were collected, all during the warmer months. These showed no vestibular and intercalary cells, and their closures were made up of chewed plants and mud mixed with organic materials and resin-coated surfaces, sometimes showing a layer of lichens. The cells were provisioned with various wild species of cockroaches (Chorisoneura sp, Riata sp and Helgaia sp) in the nymph stage and/or adults. The sex ratio was 4.6 females per male, significantly higher that the expected 1:1. Most pre-pupae entered diapause in winter with development time ranging from 187 to 283 days for females and 180 to 283 days for males. Deaths occurred in 41.66% of cells provisioned, 33.33% were attributed to faulty development and 8.33% to Chrysididae

Nesting Biology of Podium angustifrons Kohl (Hymenoptera, Sphecidae) in an Araucaria Forest Fragment

Podium angustifrons Kohl 1902 is a species of solitary wasp which nests in pre-existing cavities, with neotropical distribution in Argentina, Bolivia, Brazil, Colombia, Guyana and French Guyana. The aim of this study was to investigate the nesting biology of P. angustifrons, discussing aspects of their life history. To capture its nests, wooden trap-nests were installed in the Parque Municipal das Araucárias, Guarapuava (PR), Brazil, from January 2003 to April 2009. A total of 29 nests were collected, all during the warmer months. These showed no vestibular and intercalary cells, and their closures were made up of chewed plants and mud mixed with organic materials and resin-coated surfaces, sometimes showing a layer of lichens. The cells were provisioned with various wild species of cockroaches (Chorisoneura sp, Riata sp and Helgaia sp) in the nymph stage and/or adults. The sex ratio was 4.6 females per male, significantly higher that the expected 1:1. Most pre-pupae entered diapause in winter with development time ranging from 187 to 283 days for females and 180 to 283 days for males. Deaths occurred in 41.66% of cells provisioned, 33.33% were attributed to faulty development and 8.33% to Chrysididae

Nesting behavior of Trypoxylon (Trypargilum) agamemnom Richards (Hymenoptera: Crabronidae)

Nesting behaviour is extremely diversified among solitary nesting sphecids. Thus, the aim of this study was to describe the nesting behaviour of Trypoxylon agamemnon and discuss the advantages of guarding behaviour of males. It was conducted in the Parque Municipal das Araucárias, Guarapuava (PR), Brazil from October/2003 to July/2007. To describe the behaviour of T. agamemnon and construct its ethogram, daily observations were made, totalling 410:19 hours observation. Although the males of T. agamemnon stand guard close to the entrance of the nests, we concluded that this behaviour is not ensuring the protection of nests against parasitoids and that, probably, this behaviour ensures them the paternity, but further studies with microsatellite markers will be necessary to confirm this hypothesis