Aggregation Patterns of Sensory Sensillae in the Food Canal and Cibarium of Haematobia irritans (Diptera: Muscidae)

Although mean body lengths of females were significantly greater than males in individuals drawn from two Haematobia irritans (L.) sample populations (n = 20 females and n = 20 males from West Virginia; n = 20 females and n = 20 males from Georgia), there were no significant differences in food canal lengths for females versus males at either site. Variable numbers (21-37) of setiform sensillae occurred throughout the length of the food canal, but such sensillae were significantly aggregated in the distal-most canal region of both sexes at both sites. There was no significant difference in mean numbers of food canal setiform sensillae between females and males. Four basiconic (campaniform) sensillae were consistently observed in the food canal of every fly; always aggregated in the distal-most canal region. Setiform sensillae in the cibarium also varied in number (6-13), but were significantly aggregated in the median and proximal cibarial regions. Four (occasionally three) peg-like basiconic sensillae were also observed in the cibarium of sample individuals; always in the distal and distal median regions of both sexes. Sensory sensillae (both setiform and basiconic) in both the food canal and cibarium were similarly aggregated for both sexes at both sites. Aggregation of setiform and basiconic sensillae in the food canal suggests that the distal canal region is most critical for sensory input regarding monitoring blood flow, and stress forces brought to bear on the cuticle as the labrum tip penetrates the host's skin.

Putative Sensory Structures Associated With the Food Canal of Tabanus atratus (Diptera: Tabanidae)

Putative sensory structures in the food canal, and distal vestibule region entering the canal of Tabanus atratus F., are described. Two pairs of sensilla were observed in the walls of the vestibule-a distal pair of the basiconic type, and a pair of setifiorm sensilla at the base of the vestibule. Vestibular sensilla were constant in type, number, and position. Conversely, setiform sensilla in right and left walls of the food canal varied in number from one fly specimen to another, and lacked evidence of pairing (i.e., sensilla in one wall did not necessarily have a counterpart in the other wall). Food canal sensilla were of setiform design, with the exception of a single basiconic sensilla in each lateral wall of the food canal in every fly. When the food canal was partitioned into four equidistant regions, setiform sensilla were aggregated in the two distal-most regions, with relatively few sensilla observed in the two proximal canal regions. This aggregation was significant, leading to rejection of the null hypothesis that setiform sensilla were evenly distribution throughout the length of the food canal. Basiconic sensilla were always located in the distal-most region of the food canal.

Sensory Trichites Associated With the Food Canal of Chrysops callidus (Diptera: Tabanidae)

Twelve pairs of putative sensory trichites (= sensilla) in the food canal of Chrysops callidus Osten Sacken are described. Eight paired trichites are located in the distal half of the food canal of all flies in the sample population (n = 26 females), but paired trichites 9 through 12 were found in variable numbers in the proximal half of the canal. Trichites were more closely spaced in the distal half of the food canal, and more widely spaced in the proximal half of the canal, indicating that monitoring blood flow is more critical in the distal region of the canal. Moreover, trichites were not precisely paired, with mean position for each right wall trichite 1 through 8 being slightly anterior to its counterpart in the left wall. A short, funnel-shaped vestibule was evident at the labrum terminus, opening distally to the outside and proximally into the food canal (the vestibule/food canal junction). There were two pairs of sensilla (one pair of basicone design, the other setiform) observed at the base of the vestibule just anterior to the junction of the vestibule with the food canal. These vestibular sensilla were constant in type, number and position, in every member of the sample population.

Carrion fly (Diptera: Calliphoridae) larval colonization of sunlit and shaded pig carcasses in West Virginia, USA

Two pig (Sus scrofta L.) carcasses were placed in sunlit and shaded plots in September 2003, and again in May 2004. Mean ambient temperatures between sunlit and shaded plots were not significantly different in either September or May, but mean ambient temperatures at sunlit and shaded plots in 2004 were significantly higher than corresponding means for sunlit and shaded plots in 2003. Mean maggot mass temperatures were significantly higher than ambient plot temperatures for all four experimental plots (i.e., sunlit and shaded carcasses in both 2003 and 2004). In addition, maggot mass temperatures on sunlit carcasses were positively, and significantly, correlated with ambient temperatures, whereas there was no significant correlation between maggot mass and ambient temperatures at shaded plots. Carcass decomposition proceeded more rapidly in 2004 in the presence of higher ambient temperatures, and sunlit carcasses decomposed faster than shaded ones in both 2003 and 2004 experiments. Phaenecia coeruleiviridis (Macquart) and Phormia regina (Meigen) third instars dominated collections on all four carcasses, but there was little temporal overlap between these species with third instars of the former dominating collections in the early portion (approximately 40%) of each experimental period (with the exception of the shaded carcass in 2004 where both species were co-dominant), and the latter assuming dominance in the latter portion (approximately 60%). Lower accumulated degree hour values were calculated for instar development on 2004 carcasses subjected to higher ambient temperatures.

Occurrence of tire inhabiting mosquito larvae in different geographic regions of West Virginia

Eleven species of mosquito larvae were collected in 568 collection visits to 209 abandoned tire pile sites in 33 West Virginia counties from April through October of 2003. Ochlerotatus j. japonicus supplanted the native Oc. triseriatus as the most common tire-colonizing species in the state. In general, the exotic Oc. j. japonicus was a better colonizer of tires than Oc. triseriatus in peridomestic, sunlit conditions throughout the state, whereas both species were equally likely to colonize tires in nonperidomestic, shaded settings. Aedes albopictus competed effectively with Oc. triseriatus from mid-summer through October in low elevation western counties but was not well represented in central counties of the state. Aedes albopictus was seldom collected at higher elevations in eastern counties. Culex pipiens, like Ae. albopictus, was more likely to be in collections from the western portion of West Virginia throughout the study period. Frequency of occurrence of Cx. restuans peaked in early season collections and declined as the season progressed, but Anopheles punctipennis and the medically unimportant Cx. territans gradually increased in frequency each month through September. Typically, species in the genus Culex and An. punctipennis were predisposed to peridomestic, sunlit habitats. Larvae of the predatory Toxorhynchites rutilus septentrionalis were found mostly in nonperidomestic, shaded settings. This species initially appeared in mid-summer, and by August and September it was found in as many as 30% of the collection sites in western and eastern counties. Larvae of An. barberi, Oc. atropalpus, and Orthopodomyia signifera were poorly represented in collections.

Larval mosquitoes in abandoned tire pile sites from West Virginia

Larvae of 13 mosquito species were collected from abandoned tire piles at peridomestic and nonperidomestic sites in 3 south-central West Virginia counties from May through September 2002. Ochlerotatus triseriatus was the most frequently collected species from May through August, whereas Aedes albopictus and Ochlerotatus japonicus were more prevalent in September. Prevalence of Oc. triseriatus and Culex restuans declined throughout the study period. Conversely, prevalences of Ae. albopictus, Oc. japonicus, Culex territans, and Toxorhynchites rutilus increased during the same period. Ochlerotatus atropalpus was significantly more likely to be encountered at nonperidomestic sites. None of the other species exhibited a significant predisposition for either peridomestic or nonperidomestic sites.

Spatial and temporal variation in the mosquitoes (Diptera: Culicidae) inhabiting waste tires in Nicholas County, West Virginia

Larvae of 12 mosquito species were collected from abandoned tire piles at peridomestic and forested sites in Nicholas County, WV, from March through November of 2001. No larvae were found in March, but the numbers of species increased to 10 by July and remained relatively constant, at 9-11 in any given month, throughout November. Larvae of Ochlerotatus triseriatus (Say), the most commonly encountered species in every month of collection, were significantly more likely to be found in forested tire pile sites. Conversely, Culex restuans Theobald, Anopheles punctipennis (Say), Cx. territans Walker, and Aedes albopictus (Skuse) larvae were significantly more likely to be found in peridomestic tire piles. Larvae of the remaining seven species were either found in equal proportions at peridomestic and woodland sites, or there were too few collections to make statistical inferences. Opportunities for competitive interactions between Ae. albopictus and Oc. triseriatus in Nicholas County would be minimized because the peak occurrence of the two species differ temporally and spatially.

Larval fly activity on sunlit versus shaded raccoon carrion in southwestern West Virginia with special reference to the black blowfly (Diptera: Calliphoridae)

Larvae of Phormia regina (Meigen), Phaenicia sp., and Sarcophaga sp. were identified from raccoon carcasses placed in sunlit and shaded areas at a southwestern West Virginia site in May of 2000. Samples of larvae were taken from each carcass at 3-h intervals over a 153-h experimental period. Phormia regina was clearly the dominant species with large numbers of third instars observed at every 3-h collection period from 81 to 153 h on both carcasses. Mean lengths of third-instar P. regina larvae collected from the sunlit carcass were significantly greater than mean lengths of larvae collected from the shaded carcass. Third-instar Phaenicia sp. also appeared at 81 h on both carcasses, but relatively few (< or = 4) individuals were present in each 3-h collection sample from 81 through 126 h. Larvae of this species were not present in samples from either carcass in those 3-h intervals from 129 to 147 h. Sarcophaga sp. larvae were also collected, but only in samples taken from the sunlit carcass at 81 and 93 h. Ambient temperatures were recorded throughout the experimental period, whereas maggot mass temperatures were not recorded until the appearance of large numbers of second instars at 48 h. From 48 to 69 h, maggot mass temperatures were equivalent to ambient temperatures; but after 69 h, maggot mass temperatures were considerably elevated over ambient temperatures.

Larval habitat characterization for Aedes triseriatus (Say), the mosquito vector of LaCrosse encephalitis in West Virginia

OBJECTIVE

The principal aim of this investigation was to provide quantitative information on the frequency of occurrence for Aedes triseriatus (Say) larvae in West Virginia at 3 broad elevation categories, in different months of the year, and in specific types of larval habitats.

METHODS

Larvae were collected in 54 West Virginia counties over a 6-year period, and their occurrence was recorded for defined habitat categories.

RESULTS

Aedes triseriatus larvae were collected at 206 of the 587 sites examined and in 48 of the 54 West Virginia counties sampled.

CONCLUSION

Aedes triseriatus larvae are distributed equally across all elevation categories from March through October and are predisposed to shaded habitats.

Marijuana and medicine: assessing the science base: a summary of the 1999 Institute of Medicine report

In response to public pressure to allow the medical use of marijuana, the Office of National Drug Control Policy, Washington, DC, funded a study by the Institute of Medicine evaluating the scientific evidence for benefits and risks of using marijuana as a medicine. The report used scientific reviews, public hearings, and reports from other agencies, and was evaluated by knowledgeable advisors and reviewers. It called for heavier investment in research on the biology of cannabinoid systems, careful clinical studies of cannabinoids in clinical syndromes, analysis of cannabinoids' psychological effects on symptoms, and evaluations of the health consequences of heavy marijuana use; recommends against the use of smoked marijuana in medicine and for the development of a medical cannabinoid inhaler; and recommends that compassionate use of marijuana be considered under carefully reviewed protocols. Finally, the report evaluates the abuse potential, tolerance, withdrawal, and gateway risks of medical use of cannabinoid drugs.

Intrahepatic larval nematode infection in the northern spring peeper, Pseudacris crucifer crucifer (Anura: Hylidae), in West Virginia

Larval stages of an unknown nematode were observed encapsulated in the livers of spring peepers, Pseudacris crucifer crucifer (Weid-Neuweid), collected from a marsh in western West Virginia (USA) during the spring breeding seasons of 1993 and 1994. Prevalence and mean intensity of infection were 37% (30 of 82 animals) and 2.03 parasites per infected host, respectively. Capsules with white or darkly pigmented walls were observed in infected livers; the former containing viable larvae, and the latter enveloping larvae in various stages of degeneration.

Parasitic arthropods of white-footed mice at McClintic Wildlife Station, West Virginia

Seven species of parasitic arthropods (one sucking louse, one bot, 2 fleas, one tick, and 2 mites) were recovered from 81 white-footed mice, Peromyscus leucopus, live-trapped on the grounds of the McClintic Wildlife Station, Mason County, WV, from March through November 1990. The most commonly collected arthropods were the fleas Orchopeas leucopus (89 specimens) and Epitedia wenmanni (23), and the tick Dermacentor variabilis (38). Sex ratios for both flea species were female biased; 1.8:1.0 for O. leucopus and 1.6:1.0 for E. wenmanni.

Mosquitoes of West Virginia: an update

Nineteen species of larval mosquitoes were collected from 209 sites in 47 of West Virginia's 55 counties over a 7-month period (April-October) in 1992. Aedes abserratus is recorded from the state for the first time.

Ontogeny of the circadian system controlling release of sperm from the insect testis

In the gypsy moth, the release of sperm bundles from the testis into the vas deferens is rhythmic and is controlled by a circadian pacemaker located in the reproductive system. However, in males kept since pupation in constant darkness (DD) and temperature, the release of sperm was arrhythmic. The release of sperm became rhythmic when males were transferred from a light-dark cycle (LD 16:8) to DD 6-7 days after pupation. To further investigate the development of the circadian system during the pupal stage, we exposed DD pupae to a single 8-hr pulse of light or 8-hr pulse of a 4 degrees C temperature increase on different days after pupation. The pattern of sperm release was determined 5-6 days after the pulse. Males that were exposed to light or temperature pulses 5 days after pupation subsequently showed nonrhythmic sperm release. However, about half of the pupae that received the pulse on day 6 and most of the pupae that received it on day 7 subsequently showed synchronized sperm release. These results suggested that the clock underlying rhythmic release of sperm becomes operational at approximately 6 days after pupation--that is, 2 days prior to initiation of rhythmic sperm release from the testis.

Protein differences in tau mutant hamsters: candidate clock proteins

In the tau mutant hamster, the period of the circadian rhythm is shortened from about 24 h to about 22 h in heterozygotes and to about 20 h in homozygotes. Understanding the biochemical basis of the period changes in the tau mutant may elucidate the regulation of the vertebrate pacemaker. Using two-dimensional gel electrophoresis, we have found two sets of proteins that differ between the different genotypes. P33tau (about 33 kDa; pI 6.5) was found in all gels from wild type and heterozygous animals, but was absent in gels from all except one of the homozygous mutant animals. P32tau (about 32 kDa; pI 4.8) was a chain of spots, which showed a striking difference in pattern between gels from wild type animals and from mutant animals. P33tau was greatly enriched in soluble cellular fractions, whereas P32tau was found only in insoluble fractions. These differences between P33tau and P32tau were apparent in gels from both SCN and cortical tissue, suggesting that both proteins are distributed throughout the brain. These proteins should be useful as new tools to explore the biochemistry of circadian pacemakers.

Combined effects on the circadian clock of agents with different phase response curves: phase-shifting effects of triazolam and light

Although light provides the primary signal for the entrainment of circadian pacemakers, a number of endogenous substances and pharmacological agents are also capable of resetting circadian pacemakers. Very little is known about the combined effects of photic and nonphotic agents on clock functions. We conducted a "double-pulse" experiment, in which two discrete stimuli are presented at different times within a single circadian cycle, to determine the combined effects of a 1-hr light pulse and injections of a benzodiazepine, triazolam, on the circadian rhythm of activity in the golden hamster. Our results suggest that, first, when given together as done in these experiments, the effects of triazolam and light are partially but not completely additive. Triazolam-induced phase advances appeared to make the effects of subsequent 1-hr light pulses more negative; phase delays were increased, and phase advances were decreased. Second, it appears that triazolam and light may alter the circadian pacemaker in very different ways, beyond the obvious difference in the shape of their phase response curves. The phase-shifting mechanics of the circadian system of the golden hamster appear to involve a longer response time to triazolam than to light pulses. Alternative possibilities to account for this difference are discussed.

Single injections of triazolam, a short-acting benzodiazepine, lengthen the period of the circadian activity rhythm in golden hamsters

Single injections of the benzodiazepine, triazolam, induce phase shifts and cause a lengthening of the circadian activity rhythm in the golden hamster. The effect of triazolam on period depends on the phase of injection, but is not dependent on the direction of the phase shifts. Triazolam injections caused increases in period that were associated with phase advances as well as phase delays in the activity rhythm. This relationship between triazolam-induced phase shifts and changes in period is different from the relationship between light-induced phase shifts and period changes.

Hibernation in garter snakes (Thamnophis sirtalis parietalis): seasonal cycles of cold tolerance

1. The red-sided garter snake hibernates for about six months each year in Manitoba, Canada, where winter temperatures are often as low as -40 degrees C. Mammalian hibernators typically undergo profound changes in preparation for hibernation, but little is known about corresponding changes in reptiles. 2. We tested the importance of seasonal changes in the ability of red-sided garter snakes to hibernate successfully by exposing them to winter conditions at different times of year. 3. Animals that began hibernation in the fall were more likely to survive hibernation than animals that began hibernation in either early or late summer, despite the fact that the animals were kept on seasonally constant conditions prior to hibernation. 4. We suggest that these changes are derived from endogenous components of the yearly hibernation cycle of red-sided garter snakes but that only part of the cycle proceeds endogenously, i.e. it is not a completely endogenous circannual cycle.

Social dynamics of group courtship behavior in male red-sided garter snakes (Thamnophis sirtalis parietalis)

Mating in red-sided garter snakes is characterized by the formation of mating balls. Up to 100 males simultaneously court single females. The social dynamics of the formation of these mating balls was examined to determine whether the mating balls are formed simply because of a common attraction to the female or whether males are stimulated by the mating balls themselves. A sexually attractive female garter snake appears to be even more attractive to a male when she is being courted by other males than when she is alone. Male garter snakes courted females more actively when other males were also courting the female than when they were alone with her. There is a positive correlation between the number of additional males present and the amount of courtship activity shown by the test male toward the stimulus female. The extent to which the courtship activity of the test males was stimulated by the presence of additional courting males was not influenced by how actively the additional males courted.

Persistence of infradian body weight cycles in castrated dormice (Glis glis)

Male dormice were castrated at 2 phases of their infradian body weight cycles. No consistent changes were found in cycle period, amplitude, or absolute weights of the dormice following castration. Unlike other mammals, body weights of dormice appear unaffected by castration. Although both body weight and reproductive condition vary on an infradian basis, the changes in body weight appear to be programmed independently from changes in gonadal function.