Genetic control and development expression of malate dehydrogenase in Apis mellifera

Clinal variation and selection on MDH allozymes in honeybees in Chile

Evidence of clinal variation and selection on Mdh-1 locus was observed in 27 samples from 22 sites in a 2800 km north-south transect across Chile. We found a negative correlation among F allele normalized frequency and mean temperature, and minimum temperature of January and July, as well as a positive correlation among S allele normalized frequency and annual mean, and minimum January temperatures. Our results lend weight to the idea that Chilean honeybee populations of colder areas have higher F allele frequencies, supporting previous claims that Mdh-1 allozymes of Apis mellifera are subject to temperature-mediated selection.

Clinal variation and selection of MDH allozymes in honey bee populations

Latitudinal clines of malate dehydrogenase-1 (MDH-1) allozymes occur within honey bee populations on three continents: Europe, North America and South America. The North and South American populations are introduced and demonstrate that Mdh allelic clines were established within the last 150 years. The frequency of the 'medium' electrophoretic allele increases in frequency with increasing latitude while the 'fast' allele decreases with latitude on all the three continents. The clines are best explained by the average daily high temperature for July on all continents. These parallel clines provide evidence for selection on Mdh alleles in honey bees.

Hormonal and Genetic Control of Behavioral Integration in Honey Bee Colonies

The ability of insect colonies to adjust the division of labor among workers in response to changing environmental and colony conditions, coupled with research showing genetic effects on the division of labor in honey bee colonies, led to an investigation of the role of genetics and the environment in the integration of worker behavior. Measurements of juvenile hormone(JH) titers and allozyme analyses of worker honey bees suggest that two processes are involved in colony-level regulation of division of labor: (i) plasticity in age-dependent behavior is a consequence of modulation of JH titers by extrinsic factors, and (ii) stimuli that can affect JH titers and age-dependent behavior do elicit variable responses among genetically distinct subpopulations of workers within a colony. These results provide a new perspective on the developmental plasticity of insect colonies and support the emerging view that colony genetic structure affects behavioral organization.

Neotropical Africanized honey bees have African mitochondrial DNA

Non-indigenous African honey bees have invaded most of South and Central America in just over 30 years. The genetic composition of this population and the means by which it rapidly colonizes new territory remain controversial. In particular, it has been unclear whether this 'Africanized' population has resulted from interbreeding between African and domestic European bees, or is an essentially pure African population. Also, it has not been known whether this population expanded primarily by female or by male migration. Restriction site mapping of 62 mitochondrial DNAs of African bees from Brazil, Venezuela and Mexico reveals that 97% were of African (Apis mellifera scutellata) type. Although neotropical European apiary populations are rapidly Africanized by mating with neotropical African males, there is little reciprocal gene flow to the neotropical African population through European females. These are the first genetic data to indicate that the neotropical African population could be expanding its range by female migration.

Polymorphisms in mitochondrial DNA of European and Africanized honeybees (Apis mellifera)

This study demonstrates polymorphisms in both the length and in the restriction enzyme cleavage sites of honeybee mitochondrial DNA (mtDNA). The levels of variation are typical of those found in other metazoan species. These polymorphisms are potentially useful for the identification of Africanized bees in the western hemisphere and for study of honeybee phylogenetics.

Esterase isozymes of Apis mellifera: substrate and inhibition characteristics, developmental ontogeny, and electrophoretic variability

Starch gel electrophoresis utilizing different types of substrates and inhibitors made it possible to detect several esterases in crude extracts of Apis mellifera. Our results suggest that there are six Apis mellifera esterase isozymes (esterases 1-6) that differ not only in electrophoretic mobility but also in substrate specificity and inhibition properties. Some of the esterase isozymes are controlled by more than one allele. The frequency of these genetic variants was analyzed in four populations of Apis mellifera from several localities. Esterases 1, 2, and 4 do not exhibit developmental changes, but the electrophoretic profile of esterases 3, 4, and 6 varies during ontogenetic development.