Survey and Risk Assessment of Apis mellifera (Hymenoptera: Apidae) Exposure to Neonicotinoid Pesticides in Urban, Rural, and Agricultural Settings.

A comparative assessment of apiaries in urban, rural, and agricultural areas was undertaken in 2013 and 2014 to examine potential honey bee colony exposure to neonicotinoid insecticides from pollen foraging. Apiaries ranged in size from one to hundreds of honey bee colonies, and included those operated by commercial, sideline (semicommercial), and hobbyist beekeepers. Residues in and on wax and beebread (stored pollen in the hive) were evaluated for the nitro-substituted neonicotinoid insecticides imidacloprid and its olefin metabolite and the active ingredients clothianidin, thiamethoxam, and dinotefuran. Beebread and comb wax collected from hives in agricultural landscapes were more likely to have detectable residues of thiamethoxam and clothianidin than that collected from hives in rural or urban areas (∼50% of samples vs. <10%). The maximum neonicotinoid residue detected in either wax or beebread was 3.9 ppb imidacloprid. A probabilistic risk assessment was conducted on the residues recovered from beebread in apiaries located in commercial, urban, and rural landscapes. The calculated risk quotient based on a dietary no observable adverse effect concentration (NOAEC) suggested low potential for negative effects on bee behavior or colony health.

The Mediterranean fruit fly in California: evidence for multiple introductions and persistent populations based on microsatellite and mitochondrial DNA variability.

Microsatellite and mitochondrial DNA (mtDNA) variability data were used to study outbreaks of Mediterranean fruit fly in California in the years 1992-94 and 1997-99. A total of 359 flies caught in monitoring traps during these years were examined at three polymorphic mtDNA restriction sites and two microsatellite loci. Composite genotypes obtained through analysis of these markers indicate at least five independent introductions of medflies into California between 1992 and 1998. Whereas the majority of specimens displayed a single mtDNA haplotype (AAA), variation of microsatellite alleles among these flies suggests at least one additional introduction in 1993 into southern California. Flies displaying the AAB haplotype sampled in 1992 both in northern and southern California shared microsatellite alleles absent in AAA flies although lacking others commonly found in AAA specimens, thus supporting the hypothesis of an independent introduction of these flies from a different source. In contrast to earlier infestations, a few specimens caught in southern California in 1993 and again in 1998 showed both mtDNA and microsatellite patterns consistent with a Hawaiian origin. Single flies collected in Santa Clara County in 1997 and in El Monte, Los Angeles County & in 1999 most likely represent a sixth and seventh distinct introduction, respectively.

Optimum timing of miticide applications for control of Varroa destructor (Acari: Varroidae) in Apis mellifera (Hymenoptera: Apidae) in Washington State, USA.

Seven treatments for the control of Varroa destructor (Anderson & Trueman) were tested to determine the optimum timing of miticide application. Threshold mite levels indicating miticide application were determined for three possible treatment dates: April, August, and October. The treatments were as follows: (1) fluvalinate in April, (2) fluvalinate in August, (3) fluvalinate in October, (4) fluvalinate in April and October, (5) fluvalinate applied continuously (except during honey flow) with replacement every 42 d, (6) control (no treatment), and (7) coumaphos in April. The number of miticide applications in a season had no effect on brood area or colony bee population a year after initiating the experiment. However, the absence of any treatment significantly reduced brood area and colony bee population and significantly increased colony mite population. Date of treatment had significant effects on colony mortality rates, mite levels, and brood area the following spring. When coupled with sampling and threshold recommendations, a single, late-season application of fluvalinate is as effective for the control of V. destructor as semiannual or continuous miticide applications. Treatment thresholds were recommended for ether roll and 48-h sticky board sampling methods in April (three and 24 mites, respectively) and August (14 and 46 mites, respectively) and for ether rolls in October (three mites) in cold climates.

Intraspecific mitochondrial DNA variation in the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae).

Restriction endonuclease analyses of mitochondrial DNA (mtDNA) were used to examine genetic variability and population structure in Leptinotarsa decemlineata (Say). A group of three enzymes, EcoRI, HpaI, and PstI, was used to reveal polymorphism both within and among some of the 10 populations tested, yielding 16 haplotypes in combination. The frequencies of these 16 haplotypes differed significantly across geographic regions, indicating some partitioning of mtDNA haplotypes. Estimates of mtDNA sequence divergence (delta) between haplotypes ranged from 0.016 to 0.135%, suggesting local differentiation of mtDNA in some populations. Analysis of these data suggests that Texas was colonized by more than one mtDNA lineage, most likely originating in Mexico. We hypothesize that a larger founder size for the initial introductions or high levels of variability in the parent population at the edge of the CPB expanding range led to the initial partitioning of haplotypes observed in samples from Texas.

Molecular phylogenetics of honey bee subspecies (Apis mellifera L.) inferred from mitochondrial DNA sequence.

A mitochondrial DNA region encompassing part of the NADH dehydrogenase subunit 2 and isoleucine transfer RNA genes was PCR amplified, cloned, and sequenced for 14 morphometrically identified Apis mellifera subspecies and the New World "Africanized" honeybee. Twenty different haplotypes were detected and phylogenetic analyses supported the existence of 3 or 4 major subspecies groups similar to those based on morphometric measurements. However, some discrepancies are reported concerning the subspecies composition of each group. Based on the sequence divergence of Drosophila (2% per Myr) we found that the four lineages may have diverged around 0.67 Myr. The variability found in this region enables us to infer phylogenetic relationships and test hypotheses concerning subspecies origin, dispersion, and biogeography.

Analysis of mitochondrial DNA and development of PCR-based diagnostic molecular markers for Mediterranean fruit fly (Ceratitis capitata) populations.

A 2.99 kb mtDNA fragment containing two variable restriction endonuclease sites (EcoRV and XbaI) was subcloned and sequenced from the Mediterranean fruit fly (Ceratitis capitata). This fragment represents approximately one-fifth of the entire mitochondrial sequence. The sequence was aligned with the comparable region from Drosophila yakuba and Anopheles gambiae, resulting in 81.8% and 76.7% identity at the nucleotide level, and 77% and 67.7% identity, respectively, at the amino acid level. The sequenced region includes the complete genes for NADH dehydrogenase 4, NADH dehydrogenase 4L, NADH dehydrogenase 6, and transfer RNAs for proline, threonine and histidine, and part of the genes for NADH dehydrogenase 5 and cytochrome b. Oligonucleotide primers were designed to asymmetrically bracket each of two variable restriction endonuclease sites to allow PCR amplification and subsequent restriction endonuclease analysis of individual fly samples.

Mitochondrial DNA restriction map for the Mediterranean fruit fly, Ceratitis capitata.

Molecular genetic research on the Mediterranean fruit fly, Ceratitis capitata, will provide tools to permit determination of source populations for new pest infestations. Restriction fragment length polymorphism (RFLP) of mitochondrial DNA provides some interpopulation discrimination. A restriction map, including the informative variable EcoRV and XbaI restriction sites, is constructed for the Mediterranean fruit fly, and several restriction sites are associated with specific gene regions based on polymerase chain reaction-RFLP and sequence analyses. A partial sequence of the mitochondrial 16S ribosomal RNA gene is reported.

New allozyme variability in Italian honey bees.

Adult workers of the honey bee, Apis mellifera ligustica, from Italy were assayed for enzyme polymorphism using a variety of electrophoretic conditions. Three polymorphic enzyme systems are described, two of which, malic enzyme and an esterase, were previously unknown in indigenous A. m. ligustica. In addition, a new allozyme for the Mdh locus is reported.