Cuticular hydrocarbons ofAedes hendersoni cockerell andA. triseriatus (SAY).

Field-caught adult male and femaleAedes hendersoni are difficult to distinguish from the sibling speciesA. triseriatus. We found that mosquitoes from the same sex of the sibling species can not be readily separated either by unique cuticular hydrocarbon components or by differences in percent composition of those components. Multivariate analysis of the cuticular hydrocarbon data does not provide good separation. Cuticular hydrocarbons were identified using gas chromatography electron-impact mass spectrometry and gas chromatography chemical-ionization mass spectrometry. Flame-ionization capillary gas chromatography was used for quantitative analysis of individual mosquitoes. Sixty-four hydrocarbons with chain lengths from C16 to greater than C46 were common to both species. Identified hydrocarbon components weren-alkanes, monomethylalkanes, dimethylalkanes, trimethylalkanes, and alkenes.

Geographic variation of cuticular hydrocarbons among fourteen populations of Aedes albopictus (Diptera: Culicidae).

Cuticular hydrocarbons were used to differentiate among fourteen Aedes albopictus (Skuse) populations from Asia, Brazil, and the United States. Forty cuticular hydrocarbon peaks from each North American population were previously identified using gas chromatography electron impact-mass spectrometry. The same cuticular hydrocarbon peaks were identified in the Asian and Brazilian populations. Samples from three populations were analyzed using capillary gas chromatography chemical ionization mass spectrometry. Total carbon number and branch points were found for four peaks which occurred at equivalent chain lengths > 38.65. Quantitative analyses were performed by flame ionization gas chromatography. All populations contained the same cuticular hydrocarbons but showed differences in percentage composition. Nine of the 14 populations were separable by discriminant analysis of hydrocarbon components. Overlap of the 95% CIs occurred between the two Brazilian populations and among three North American populations. Individual specimens from three North American populations were used as a test group in the discriminant analysis. Correct classification of these individuals by population ranged from 80 to 100%.

Tree hole Culicoides (Diptera: Ceratopogonidae) of the Central Plains in the United States.

Three-hundred eleven tree holes were sampled for Culicoides at 27 localities in Colorado, Kansas, Nebraska, Oklahoma and South Dakota. Of the 311 samples taken, 170 produced specimens, and 2,899 Culicoides were collected including 12 species. The 5 most common species (number collected) were C. guttipennis (1,468), C. arboricola (355), C. paraensis (292), C. elemae (186) and C. footei (159). Other species collected were C. villosipennis, C. nanus, C. hinmani, C. oklahomensis, C. snowi, C. lahillei and C. byersi. New state records include C. byersi and C. arboricola for Colorado; C. arboricola for Wyoming; and C. lahillei, C. elemae, C. nanus and C. paraensis for Oklahoma. Culicoides byersi, whose larval habitat was previously unknown, was reared from a cottonwood tree hole.

Cuticular hydrocarbon geographic variation among seven North American populations of Aedes albopictus (Diptera: Culicidae).

Cuticular hydrocarbons were used to differentiate among the following North American populations of Aedes albopictus: Chicago, Ill.; Milford, Del.; Jacksonville, Fla.; San Antonio, Tex.; New Orleans, La.; Houston, Tex.; and Lexington, Ky. Forty cuticular hydrocarbon peaks were identified from each population using gas chromatography electron impact-mass spectrometry: 16 n-alkanes, 21 monomethylalkanes, and 3 dimethylalkanes. Fourteen peaks occurred at equivalent chain lengths greater than 38.65 and consisted of complex mixtures of dimethyl- and trimethylalkanes. Quantitative analyses were performed on pooled samples of five females from each population using flame ionization gas chromatography. All populations contained the same cuticular hydrocarbons, but showed differences in percent composition. Five of seven populations were separable by discriminant analysis of hydrocarbon components.

Habitat and temporal partitioning of tree hole Culicoides (Diptera: Ceratopogonidae).

Spring emergence patterns of tree hole Culicoides were examined at 11 geographic locations. Habitat selection was one mechanism of partitioning used by Culicoides. One group (3 species) occupied tree holes with standing water (wet), while the other (7 species) inhabited tree holes without standing water (dry). The wet tree hole species had sustained emergence patterns, emergence maintained over several consecutive weeks. The dry tree hole species had phasic or biphasic emergence lasting fewer days or occurring as 2 short periods. In both dry and wet habitats, species emerged in a temporal sequence. This temporal sequence was disrupted if a species occupied a type of tree hole (wet/dry) from which it did not normally occur.

Habitat pH characteristics of tree hole Culicoides (Diptera: Ceratopogonidae).

Ten species of Culicoides were collected from 166 tree holes at 20 widely separated geographic locations to assess relationships with habitat pH. Wet tree holes (containing standing water) had a mean pH of 7.46 while dry tree holes (no standing water) had a mean pH of 8.60. Culicoides arboricola, C. guttipennis and C. villosipennis occurred in wet tree holes that had mean pH values of 7.66, 7.95 and 7.31, respectively. Dry tree holes, where C. hinmani, C. elemae, C. paraensis, C. nanus, C. snowi and C. footei occurred, had pH values ranging from 8.13 to 9.08. Culicoides lahillei, a dry tree hole species, was collected from habitats with a pH range similar to the wet tree hole species.

Culicoides (Diptera: Ceratopogonidae) species in southeastern Nebraska.

Twenty-four species of Culicoides were collected between April and September of 1986 from Nemaha and Richardson counties of southeastern Nebraska using New Jersey light traps and tree hole sampling. Light trap samples were dominated by C. crepuscularis (42.4%), C. stellifer (29.6%), C. haematopotus (17.4%), C. variipennis (4.1%) and C. obsoletus (2.8%). Culicoides guttipennis and C. villosipennis were the most common of the 9 tree hole species collected. New state records for Nebraska were obtained for C. lahillei, C. riggsi, C. footei, C. paraensis, C. nanus, C. spinosus, C. biguttatus and C. piliferus.