No abstract

Animal societies exhibit remarkable variation in their breeding strategies. Individuals can maximize their fitness by either reproducing or by helping relatives. Social hymenopterans have been key taxa for the study of Hamilton’s inclusive fitness theory because the haplodiploid sex-determination system results in asymmetric relatedness among breeders producing conflict over the partitioning of reproduction. In small cooperative groups of insects, totipotent individuals may maximize their inclusive fitness by controlling reproduction despotically rather than helping their relatives. Here, we demonstrate that the dominant females of the primitively eusocial bee Euglossa melanotricha (Apidae: Euglossini) control reproduction, but concede part of the reproductive output with their related and unrelated subordinates. As expected, a dominant female capitalizes on the direct reproduction of related subordinates, according to her interests. We found that reproductive skew was positively correlated with relatedness. The concessions were highly reduced in mother-daughter and sibling nests (relatedness r ± s.d. = 0.54 ± 0.02 and 0.79 ± 0.02, respectively) but much more egalitarian in unrelated associations (r = −0.10 ± 0.01). We concluded that reproductive skew in these primitively eusocial bees is strongly related to the genetic structure of associations, and also that females are able to assess pairwise relatedness, either directly or indirectly, and use this information to mediate social contracts.

The South America encompasses the highest levels of biodiversity found anywhere in the world and its rich biota is distributed among many different biogeographical regions. However, many regions of South America are still poorly studied, including its xeric environments, such as the threatened Caatinga and Cerrado phytogeographical domains. In particular, the effects of Quaternary climatic events on the demography of endemic species from xeric habitats are poorly understood. The present study uses an integrative approach to reconstruct the evolutionary history of Partamona rustica, an endemic stingless bee from dry forest diagonal in Brazil, in a spatial-temporal framework. In this sense, we sequenced four mitochondrial genes and genotyped eight microsatellite loci. Our results identified two population groups: one to the west and the other to the east of the São Francisco River Valley (SFRV). These groups split in the late Pleistocene, and the Approximate Bayesian Computation approach and phylogenetic reconstruction indicated that P. rustica originated in the west of the SFRV, subsequently colonising eastern region. Our tests of migration detected reduced gene flow between these groups. Finally, our results also indicated that the inferences both from the genetic data analyses and from the spatial distribution modelling are compatible with historical demographic stability.

Mexican fruit flies, Anastrepha ludens (Loew; Diptera: Tephritidae), have traditionally been trapped in citrus orchards in Mexico using protein hydrolysates as bait. Recently, CeraTrap(®), an enzymatic hydrolyzed protein, has emerged as an effective lure for monitoring A. ludens at the orchard level and is currently being used by growers in the region of Veracruz. Several studies have revealed that grape juice is highly attractive to A. ludens, and recent work supports its potential use for regulation purposes. In our study, the attraction of A. ludens to different grape products was evaluated in citrus orchards and in comparison to other Anastrepha species in an area composed of mango and chicozapote orchards. Attraction to grape lures was compared with CeraTrap and the standard protein Captor +borax trap. In general, CeraTrap was more attractive than different commercial grape products in several experiments. Only Jumex, a commercial grape juice, did not differ significantly from CeraTrap in the capture of A. ludens males and females in a citrus crop. However, several drawbacks were detected when using Jumex grape juice: 1) higher tendency to capture males, 2) less selectivity against non-targeted insects, 3) higher capture of beneficial lacewings, and iv) the need to re-bait weekly owing to lower stability. In the area containing mango and chicozapote, CeraTrap was more attractive than Captor + borax for Anastrepha obliqua and Anastrepha serpentina, followed by grape juice products, which were the least attractive for these fruit fly species.