Effect of lodging type on the internal temperature and humidity of colonies of Melipona colimana (Hymenoptera: Meliponini) from a Mexican temperate zone

Stingless bees are mainly tropical insects and only a few species live in temperate climates. Melipona colimana is a stingless bee endemic to temperate areas of western Mexico, where there is much interest in exploiting it for honey production and crop pollination. It is not known, however, if colonies of this species would adapt to hives necessary for commercial exploitation. Twenty four colonies were transferred to trunks and wooden boxes having walls with one of two thicknesses (2.5 and 10.0 cm). The internal and ambient temperature and humidity were monitored for three months during winter, at the end of which, the brood cell numbers, number of adults, and nest weights were assessed. There were differences in temperature (F 1 = 69.32; F 2 = 1769.33; DF = 3, 56; P < 0.05) and humidity (F 1 = 397.15; F 2 = 1028.11; DF = 3, 56; P < 0.05) between environmental data and internal data of nests during day 1 and night 2, respectively. The internal temperature was statistically similar during the day in all three lodgings, but at night the nests in thick wooden boxes had higher temperatures compared with the other two. There was a decrease in the development of the nests and bee populations in all three lodgings, and a lowest development occurred in thin-walled boxes, probably due to thickness reduction in the lodging walls. This bee species appears capable of maintaining control of the internal environment and this ability is enhanced by using greater thickness of the lodging walls as in this study. The use of boxes with thick walls is recommended for better nest development. � 2011 IBRA

A behavioral guard caste in a primitively eusocial orchid bee, Euglossa viridissima, helps defend the nest against resin theft by conspecifics

Defense castes are know from highly eusocial insects yet have rarely been described in social species with a small colony size. In nests of Euglossa viridissima, an orchid bee exhibiting primitively eusocial behavior, we recorded one subordinate female per nest to specialize in guarding in the presence of a dominant and a second subordinate who specialized in foraging. Guarding may have arisen as a response to cleptobiosis by conspecifics, as nests with a guard more successfully avoided intrusion and resin theft

Nesting sites, nest density and spatial distribution of Melipona colimana Ayala (Hymenoptera: Apidae: Meliponini) in two highland zones of Western, Mexico

Melipona colimana Ayala is endemic to the temperate forests of western Mexico and may be in conservation risk due to forest exploitation. Differences between the density of nests, nesting sites and spatial distribution in two places with different levels of human disturbance were established. A preserved (P) and a disturbed area (D) were identified: the forest had not been exploited for more than 18 years in the P zone, while there had been recent forest exploitation of D zone in less than two years. It was determined that nesting sites, nest density and the number of potential nest sites were predominant in the P zone. In total, 27 of 30 colonies were found on oak trees (Quercus laurina) with a diameter at breast height of 183.4 � 34.21 cm which shows a close relationship of this bee species with this type of tree. A positive correlation between the DBH of the nesting sites in relation to the trees with nests and the presence of cavities was found. The nests are distributed in the form of aggregates in P and D zones (R = 0.31 and 0.39) with a density of 0.17 ha-1 and 0.04 ha-1 colonies respectively. Forestry exploitation seems to be affecting wild populations since the trees that bees use as nesting sites are destroyed in D zone

Morphological and molecular characters reveal differentiation in a Neotropical social bee, Melipona beecheii (Apidae : Meliponini)

Morphometrics and DNA microsatellites were used to analyse the genetic structure of populations of the stingless bee M. beecheii from two extremes of its geographic range. The results showed that populations from Costa Rica and Yucatan exhibit substantial phenotypic and molecular differentiation. Bees from Yucatan were smaller and paler than those from Costa Rica. The value of multilocus $F_{ST }$ = 0.280 ($P <$ 0.001) confirmed that there were significant molecular genetic differences between the two populations. Populations showed significant deviation from Hardy Weinberg equilibrium and the values of $F_{IS}$ (the inbreeding coefficient) were positive for Costa Rica = 0.416 and the Yucatan Peninsula = 0.193, indicating a lack of heterozygotes in both populations possibly due to inbreeding. The DNA sequence of 678 bp of the mitochondrial gene COI differed between populations by 1.2%. The results of this study should be considered in conservation programmes, particularly with regard to the movement of colonies between regions

Behavior and pollination efficiency of Nannotrigona perilampoides (Hymenoptera: Meliponini) on greenhouse tomatoes (Lycopersicon esculentum) in subtropical México

The acclimation, foraging behavior, and pollination efficiency of stingless bees of the species Nannotrigona perilampoides Cresson were evaluated in tomato (Lycopersicon esculentum Mill.) plants cultivated in two greenhouses. The greenhouses were divided into three areas of 16 m 2, and one of the following treatments was used for pollination: stingless bees (SB), mechanical vibration (MV), and no pollination (NP). Observations were conducted once a week from 0800 to 1600 hours during 2 mo. The acclimation of the bees to the greenhouses was estimated by the number of bees that did not return to the hive (lost bees) and by comparing the population of the colonies (brood and adults). The foraging activity of the bees across the day was evaluated by comparing the number of foragers per hour. The influence of environmental variables on the foraging activity was also analyzed. The pollination efficiency was compared among treatments through the percentage of fruit set, weight of individual fruit, kilograms of fruit produced per square meter, and the number of seed per fruit. The bees started foraging on the flowers ?7 d after the colonies were introduced to the greenhouse. There was a decline in the population of the colonies across the experiment, but colonies did not die out. Correlations of environmental variables with the foraging activity of the bees showed that none of them had a significant influence on pollen foraging. However, water collection was positively correlated with the temperature and negatively correlated with the humidity inside the greenhouse. The estimation of the pollination efficiency per treatment showed that there were significant differences in fruit set in SB (83 Zapotitlán 4.2) and MV (78.5 Zapotitlán 6.4) compared with NP (52.6 Zapotitlán 7.6). However, the average weight of the fruit was similar for the three treatments (65 g). There were significant differences for seed number in SB (200 Zapotitlán 15.3) and MV (232 Zapotitlán 21.4) compared with NP (120 Zapotitlán 16.6). The productivity in kilograms of fruit per square meter was higher in SB (5.72 Zapotitlán 0.61) and MV (5.66 Zapotitlán 0.58 kg) compared with NP (3.34 Zapotitlán 0.72). The number of seed was positively correlated with the weight of the fruit. We conclude that the use of Nannotrigona testaceicornis Rondani, for pollinating greenhouse tomatoes in tropical climates, could be an alternative to the use of highly defensive African-derived Apis mellifera or non-native bumble bees (Bombus spp.). However, more research is needed to evaluate the cost/benefit on large-scale greenhouse pollination using N. perilampoides Cresson against other bee species and pollination methods

comitato di redazione

The objective of this study was to evaluate the temperature sensitivity of three stingless bee species, one from the tropical highland transition Neartic-Neotropical region (Melipona colimana) and two from the tropical lowland regions (Melipona beecheii and Scaptotrigona hellwegeri) of Mexico. The changes in thoracic temperature, behavior, and mortality rate of workers and pupae of the three species submitted to control high and low temperatures were assessed. Workers of highland M. colimana regurgitated water and fanned their wings when submitted to high temperatures, a behavior reported here for the first time in a stingless bee. M. colimana consumed syrup and increased its thoracic temperature in response to cold environment. Workers and pupae of M. colimana experienced lower mortality rates than M. beecheii and S. hellwegeri. The results of this study showed the tolerance of M. colimana to a wider temperature range, possibly as a response to extreme conditions in its native environment. The implications of thermal susceptibility differences for the conservation of highland and lowland stingless bees are discussed. © 2011 INRA, DIB-AGIB and Springer Science+Business Media B.V

Highly polymorphic DNA markers in an Africanized honey bee population in Costa Rica

Two genetic markers (the mtDNA COI-COII intergenic region and the microsatellite A7) with high levels of variability in South African and European honey bees were analyzed in wild swarms of Africanized honey bees (Apis mellifera) from Costa Rica. Allelic or haplotypic frequencies revealed high levels of genetic variability at these loci in this population. Most of the alleles were African alleles, although some European-derived alleles were also present. Differences in the frequencies of African alleles between African and Africanized samples were minor, which could be explained by founder effects occurring during the introduction of African honey bee populations into South America.<br>Dois marcadores genéticos (a região intergénica mitocondrial COI-COII e o microsatélite A7), com altos níveis de variabilidade em populações de abelhas melíferas da África do Sul e Europa, foram analisados em uma amostra de enxames naturais da Costa Rica. As freqüências alélicas e haplotípicas na amostra africanizada mostraram altos níveis de diversidade nestes loci. A maioria dos alelos são de origem africana, embora alguns alelos de origem européia foram observados. As mudanças nas freqüências dos alelos de origem africana entre as abelhas da África do Sul e as abelhas da população africanizada são de baixa magnitude e podem ter sido causadas pelo efeito fundador que ocorreu na introdução da abelha africana na América do Sul