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Mosquitoes have developed specialized oviposition strategies that allow them to develop in a wide variety of aquatic habitats. Environmentally cued hatching traits may also play an important role in the successful colonization of some larval habitats, but this subject has remained largely unexplored in Culicidae. Aedes atropalpus (Coquillett) is an autogenous rock pool specialist that may maintain unique adaptations for oviposition and egg hatching. We investigated the egg-laying strategies of Ae. atropalpus exposed to standard (non-diapausing) rearing conditions and diapause-inducing conditions and tested the impact of physical agitation on egg hatch rates by exposing floating and submerged eggs to physical agitation treatments. The results of the oviposition experiment indicate that Ae. atropalpus females primarily lay non-diapausing eggs directly onto the water surface and lay diapausing eggs directly on solid surfaces. The egg-hatching experiment demonstrated that physical agitation significantly increases Ae. atropalpus hatch rates. Floating and submerged eggs responded similarly to the agitation treatment. These data suggest that oviposition behaviors based on both egg diapause status and environmentally-cued hatching strategies may be important adaptations for Ae. atropalpus in riverine rock pools., (© 2020 The Society for Vector Ecology.)

To assess how a grate covering a catch basin impacts oviposition by Culex mosquitoes, a field study was conducted in south Florida using containers with two types of covers, with openings of equal area, but different configurations. One opening mimicked a catch basin grate with 16 small openings, while the other cover had just one large opening. The number and presence of egg rafts in six of each container and cover combination was recorded over 18 nights at two field sites, consisting of a wastewater management facility area and residential subdivision. Three mosquito species, all belonging to the subgenus Culex accounted for more than 99% of total egg rafts collected: Culex nigripalpus ( n = 1766), Culex quinquefasciatus ( n = 754) and Culex coronator ( n = 526). Approximately 90% of Cx. nigripalpus and Cx. coronator egg rafts were deposited in the containers with the large opening cover; whereas more Cx. quinquefasciatus egg rafts were laid in the containers with small opening covers than those of Culex nigripalpus and Culex coronator combined. Similar patterns of egg laying activity were noted at each sampling stations. These results suggest that for locating oviposition sites Culex quinquefasciatus may rely more on olfactory clues, while other Culex species depend more on visual clues.

The native rock pool mosquito, Aedes atropalpus (Coquillett), and the invasive Aedes japonicus (Theobald) have been found in many types of artificial and natural containers throughout North America. Little is known about the ecology of these two species in habitats where they co-occur, although multiple investigators have reported the decline of the native species concurrent with the introduction and spread of the invasive species. Here we report the results of riverine rock pool collections (n=503) in the southern Appalachian Mountains between 2009-2015. Surface water temperatures strongly predicted the presence of each species across a broad range of observed temperatures (11-39.8° C). For every unit of increase in temperature (°C) the odds of collecting Ae. atropalpus larvae increased by 0.34 while the odds of collecting Ae. japonicus larvae decreased by 0.28. No Ae. japonicus larvae or pupae were collected at temperatures greater than 36° C; however, immature Ae. atropalpus were found in rock pools with temperatures up to 39.8° C. In contrast, Ae. japonicus were highly abundant in cooler rock pools (<17° C) where Ae. atropalpus were infrequent or absent. Our findings suggest that in spite of the successful invasion by Ae. japonicus, Ae. atropalpus remains well established in the southern Appalachian Mountains. Given the strong correlation of temperature with the presence of the two species and the contrasting absence of each species at observed temperature extremes, the role of thermal conditions should be carefully explored in the context of other ecological factors likely influencing the range and abundance of these mosquitoes., (© 2019 The Society for Vector Ecology.)

Abstract Ornithophilic Culex species are considered the primary amplification vectors of West Nile virus (WNV) in bird hosts as well as vectors responsible for epidemic transmission. Culex coronator was first collected from Okaloosa, Santa Rosa, Walton, and Washington Counties in Florida in 2005 and has since spread throughout the state. The vector competence of Cx. coronator for WNV, known to be infected in nature, has not been assessed. Without this knowledge, we are unable to assess this species' potential as an enzootic and epidemic vector of WNV in Florida. In the current study, we investigate the reproductive biology and susceptibility to WNV infection, dissemination, and transmission by Cx. coronator. We show that Cx. coronator is capable of delaying oviposition for several weeks after blood feeding and that the number of eggs laid is greater for avian than mammalian hosts. Cx. coronator were highly susceptible to infection (∼80-100%) and dissemination (∼65-85% by 18 days since exposure) with lower rates of transmission (0-17% at 25°C and 28-67% at 28°C), suggesting that it is a competent vector of WNV under some conditions. The proportion of mosquitoes with disseminated infections related to the time since exposure and was higher at 28°C than at 25°C. The rapid and statewide distribution of Cx. coronator throughout Florida poses as a potential public health risk. This baseline knowledge is essential information for mosquito control and public health agencies to assess current and future disease risk to Southeastern United States.

Within 2 yr of the arrival of the invasive container mosquito Aedes albopictus (Skuse), the previously dominant invasive mosquito Aedes aegypti (L.) disappeared from many Florida cemeteries. At some cemeteries, however, Ae. aegypti populations seem stable despite Ae. albopictus invasion. We sought to understand this variation in the outcome (exclusion, coexistence) of this invasion, given that previous experiments show that Ae. albopictus is the superior larval competitor. We tested experimentally the hypothesis that climate-dependent egg survivorship differs between exclusion and coexistence cemeteries and that differences in invasion outcome are associated with microclimate. Viability of eggs oviposited in the laboratory and suspended in vases at six cemeteries was significantly greater for Ae. aegypti than for Ae. albopictus, and greater in 2001 than in 2006. Cemeteries differed significantly in egg survivorship of Ae. albopictus, but not of Ae. aegypti, which is consistent with the hypothesis that Ae. albopictus suffers site-specific, climate-driven egg mortality that mitigates the competitive superiority of larval Ae. albopictus. Principal component (PC) analysis of microclimate records from vases during the experiments yielded three PCs accounting for >96% of the variance in both years of experiments. Multivariate analysis of variance of the three PCs revealed significant microclimate differences among the six cemeteries and between exclusion versus coexistence cemeteries. Stepwise logistic regression of egg survivorship versus microclimate PCs yielded significant fits for both species, and twice as much variance explained for Ae. albopictus as for Ae. aegypti in both years. Higher mortalities in 2006 were associated with high average daily maximum temperatures in vases, with lethal thresholds for both species at ≈40°C. From 1990 to 2007, vase occupancy by Ae. albopictus increased and that by Ae. aegypti decreased, with increasing seasonal precipitation at one well-sampled cemetery. Results support the hypothesis that locally variable climate-driven mortality of Ae. albopictus eggs contributes to patterns of exclusion of, or coexistence with, Ae. aegypti.

Patterns of seasonal variation in the relative abundance of immature Culex mosquitoes in wastewater ponds at dairies located in 2 different regions of peninsular Florida were compared. Culex nigripalpus and Cx. quinquefasciatus were by far the most common mosquitoes collected during the study (99,344 and 106,225 individuals, respectively). Within-station differences in abundance of Cx. nigripalpus and Cx. quinquefasciatus were evident depending upon time of year. There were also between-station differences in the abundances of the 2 species depending upon time of year and station. Environmental and behavioral factors are implicated in some of the observed differences. We discuss mosquito control options for dairy ponds as well as possible impacts of mosquito production from these areas to humans and to animal health and production.

Geographic variation in species interactions can have major effects on distributions. Effects of such variation can be particularly evident for invasive species, in which variation in competitive ability can influence invasive success and impacts. We tested the hypothesis that coexistence or exclusion of the resident mosquito Aedes aegypti results from variation among local populations of the invasive Aedes albopictus in competitive interactions with A. aegypti. We also examined the role of variation in fecundity-size relationships in these competitive interactions. We compared competitive abilities of nine North American populations of A. albopictus, three populations from each of three site types: extinction of A. aegypti following A. albopictus invasion, coexistence following A. albopictus invasion, and A. albopictus allopatric to A. aegypti. Competition among larvae from each A. albopictus population and a single A. aegypti population was tested in laboratory microcosms in a response surface design. We found interpopulation differences in competitive ability of A. albopictus, but no strong patterns among site types. Extinction sites had steeper average fecundity-size relationships than coexistence sites and allopatric sites, but this did not translate into superior population performance. Certain individual A. albopictus populations had exceptionally large competitive effects on A. aegypti or poor competitive responses to competition from A. aegypti, but competitive effect and response were not correlated. These results suggest that interpopulation variation in the competitive ability of A. albopictus may only partly explain the geographic pattern of coexistence with or extinction of A. aegypti. Environmental differences among regions may affect the competitive ability of A. albopictus and influence its invasion success and impact.

Non-selective benzodiazepines, such as diazepam, interact with equivalent affinity and agonist efficacy at GABA(A) receptors containing either an alpha1, alpha2, alpha3 or alpha5 subunit. However, which of these particular subtypes are responsible for the anticonvulsant effects of diazepam remains uncertain. In the present study, we examined the ability of diazepam to reduce pentylenetetrazoLe (PTZ)-induced and maximal electroshock (MES)-induced seizures in mice containing point mutations in single (alpha1H101R, alpha2H101R or alpha5H105R) or multiple (alpha125H-->R) alpha subunits that render the resulting GABA(A) receptors diazepam-insensitive. Furthermore, the anticonvulsant properties of diazepam, the alpha1- and alpha3-selective compounds zolpidem and TP003, respectively, and the alpha2/alpha3 preferring compound TP13 were studied against PTZ-induced seizures. In the transgenic mice, no single subtype was responsible for the anticonvulsant effects of diazepam in either the PTZ or MES assay and neither the alpha3 nor alpha5 subtypes appeared to confer anticonvulsant activity. Moreover, whereas the alpha1 and alpha2 subtypes played a modest role with respect to the PTZ assay, they had a negligible role in the MES assay. With respect to subtype-selective compounds, zolpidem and TP003 had much reduced anticonvulsant efficacy relative to diazepam in both the PTZ and MES assays whereas TP13 had high anticonvulsant efficacy in the PTZ but not the MES assay. Taken together, these data not only indicate a role for alpha2-containing GABA(A) receptors in mediating PTZ and MES anticonvulsant activity but also suggest that efficacy at more than one subtype is required and that these subtypes act synergistically.

Mosquito production from drains and catch basins in the cities of Vero Beach and Key West, FL were monitored from May 2004 through August 2005. A total of 48,787 mosquitoes were captured during the study. Of these, over 99% belonged to two species, Culex nigripalpus Theobald (2,630) and Culex quinquefasciatus Say (45,946). Other species collected included Culex restuans Theobald, Culex salinarius Coquillett, Aedes aegypti (L.), Aedes albopictus (Skuse), and Uranotaenia lowii Theobald. Significantly greater numbers of Cx. nigripalpus were collected at Vero Beach than at Key West, but no significant differences in numbers of Cx. quinquefasciatus and in total numbers of mosquitoes between the two cities were evident. Rainfall, salinity, type of structure, structure setting, and presence or absence of predators or competitors influenced the numbers of mosquitoes collected and/or the frequency of positive, negative, dry, or flooded samples.

Variations in diagnostic siphonal characters of Culex quinquefasciatus larvae collected in Key West and Vero Beach, FL, are described. We observed specimens with 3, 4, and 5 sets of siphonal setae and also observed frequent variation in the insertion point of the proximal and subapical setae.

Several techniques were used to sample adult and immature mosquitoes in 4 constructed treatment wetlands in Florida. Adults of 19 species (7 genera) of mosquitoes were collected, and immatures of the most abundant species and of 60% of all species also were collected. Few significant differences between sites and stations in the numbers of mosquitoes collected were discovered. Culex nigripalpus Theobald was the most abundant mosquito found in adult (carbon dioxide-baited suction traps) and ovitrap collections, whereas Mansonia spp. and Uranotaenia spp. were most common in pump-dip-grab samples. The roles of rooted and floating vegetation and of water quality in determining mosquito production from these areas are discussed.

Over the last decade, sequencing and characterisation of the mouse genome has been accompanied by unparalleled advances in functional genomics. In the context of drug action, we analyse the strengths and limitations of classical mutagenesis and gene targeting techniques, as well as alternative approaches such as chemical mutagenesis, gene trap, recombineering, transposon-mediated mutagenesis, chromosomal engineering, viral transgenesis and RNA interference. This review also focuses on the emerging importance of genetic manipulation in other species and related logistical issues of experimental work using mutants.:, (� 2006 Elsevier Ltd . All rights reserved.)

Schizophrenia is a chronic and debilitating disease which is thought to arise from a neuro-developmental disorder. Both the stable tubule-only polypeptide (STOP) protein and the N-methyl-D-aspartate (NMDA) NR1 subunit are involved in neuronal development and physiology. It has therefore been postulated that transgenic mice lacking either the STOP or the NMDAR1 gene would show a 'schizophrenic-like' phenotype. Here, STOP knockout and NMDA NR1 hypomorphic mice were assessed in a behavioural measure that can be used to detect schizophrenic-like phenotypes: a change in sensorimotor gating, measured through prepulse inhibition (PPI). STOP knockout mice were further assessed in another measure of 'schizophrenic-like behaviour': hyperlocomotion. The PPI deficit exhibited by both the STOP knockout and NMDA knockdown mice could not be reversed by acute treatment with the atyptical antipsychotic, clozapine (1 mg/kg, i.p.) but the hyperlocomotion shown by the STOP knockout mice was reversed with the same acute dose of clozapine.

The i.v. agent etomidate exerts its anaesthetic actions through potentiation of gamma-aminobutyric acid-A receptors containing beta2 and beta3 subunits. It was recently shown that the beta2 subunit contributes to the sedative properties of etomidate, whereas the beta3 subunit is responsible for its anaesthetic properties. However, these studies evaluated anaesthetic effects in point mutation mice in which the effect of etomidate was decreased, but not abolished, at the beta2 subunit. Here we have used beta2 knockout mice to completely remove any contribution of the beta2 subunit to the effects of etomidate. Etomidate was equally anaesthetic in wildtype and knockout mice, thus further confirming that efficacy at the beta3 subunit only is sufficient to induce general anaesthesia.

The inhibitory tone maintained throughout the central nervous system relies predominantly on the activity of neuronal GABAA (gamma-aminobutyric acid type A) receptors. This receptor family comprises various subtypes that have unique regional distributions, but little is known about the role played by each subtype. The majority of the receptors contain a gamma2 subunit and are sensitive to modulation by BZs (benzodiazepines), but differ with regard to alpha and beta subunits. Mutagenesis studies combined with molecular modelling have enabled a greater understanding of receptor structure and dynamics. This can now be extended to in vivo activity through translation to genetically modified mice containing these mutations. Ideally, the mutation should leave normal receptor function intact, and this is the case with mutations affecting the BZ-binding site of the GABAA receptor. We have generated mutations, which affect the BZ site of different alpha subunits, to enable discrimination of the various behavioural consequences of BZ drug action. This has aided our understanding of the roles played by individual GABAA receptor subtypes in particular behaviours. We have also used this technique to explore the role of different beta subunits in conferring the anaesthetic activity of etomidate. This technique together with the development of subtype-selective compounds facilitates our understanding of the roles played by each receptor subtype., (Copyright 2004 Biochemical Society)

Background: The authors have previously described that the gamma-aminobutyric acid type A (GABAA) receptor beta 2N265S mutation results in a knock-in mouse with reduced sensitivity to etomidate. After recovery from etomidate anesthesia, these mice have improved motor performance and less slow wave sleep. Because most clinically used anesthetics produce hypothermia, the effect of this mutation on core body temperature was investigated., Methods: The effect of etomidate and propofol on core body temperature were measured using radiotelemetry in freely moving GABAA receptor beta 2N265S mutant mice and wild-type controls., Results: beta 2N265S mutant mice have a reduced hypothermic response to anesthetic doses of etomidate compared with wild-type controls and after a transient loss of righting reflex regain normothermia more rapidly compared with wild-type controls. Subanesthetic doses of etomidate produce hypothermia, which was not observed in the mutant mice. Vehicle administration resulted in a stress-induced hyperthermic response in both genotypes. Propofol produced a hypothermic response that was similar in both genotypes., Conclusions: The GABAA receptor beta 2 subunit mediates a significant proportion of the hypothermic effects of etomidate. As the beta 2 subunit mediates postrecovery ataxia and sedation, anesthetic agents that do not have in vivo potency at beta 2 subunit-containing receptors offer the potential for surgical anesthesia with improved recovery characteristics.

We tested whether interspecific competition from Aedes albopictus had measurable effects on A. aegypti at the typical numbers of larval mosquitoes found in cemetery vases in south Florida. We also tested whether the effect of interspecific competition from A. albopictus on A. aegypti differed between sites where A. aegypti either persists or went extinct following invasion by A. albopictus. Similar experiments manipulating numbers of A. albopictus in cemetery vases were conducted at three sites of A. aegypti persistence and three sites where A. aegypti was apparently extinct. The experiments were done using numbers of larvae that were determined by observed numbers of larvae for each site, and with resources (leaf detritus) that accumulated in experimental vases placed into each field site. In both the early rainy season (when number of mosquito larvae was low) and the late rainy season (when number of mosquito larvae was high), there was a significant effect of treatment on developmental progress of experimental A. aegypti. In the late rainy season, when numbers of larvae were high, there was also a significant effect of treatment on survivorship of A. aegypti. However, the competition treatment x site type (A. aegyptipersists vs extinct) interaction was never significant, indicating that the competitive effect of A. albopictus on A. aegypti did not differ systematically between persistence versus extinction sites. Thus, although competition from A. albopictus is strong under field conditions at all sites, we find no evidence that variation in the impact of interspecific competition is associated with coexistence or exclusion. Interspecific competition among larvae is thus a viable explanation for exclusion or reduction of A. aegypti in south Florida, but variation in the persistence of A. aegypti following invasion does not seem to be primarily a product of variation in the conditions in the aquatic environments of cemetery vases., (Copyright 2004 Springer-Verlag)

The specific mechanisms underlying general anesthesia are primarily unknown. The intravenous general anesthetic etomidate acts by potentiating GABA(A) receptors, with selectivity for beta2 and beta3 subunit-containing receptors determined by a single asparagine residue. We generated a genetically modified mouse containing an etomidate-insensitive beta2 subunit (beta2 N265S) to determine the role of beta2 and beta3 subunits in etomidate-induced anesthesia. Loss of pedal withdrawal reflex and burst suppression in the electroencephalogram were still observed in the mutant mouse, indicating that loss of consciousness can be mediated purely through beta3-containing receptors. The sedation produced by subanesthetic doses of etomidate and during recovery from anesthesia was present only in wild-type mice, indicating that the beta2 subunit mediates the sedative properties of anesthetics. These findings show that anesthesia and sedation are mediated by distinct GABA(A) receptor subtypes.

At several locations in south Florida, water impounded by the leaf axils of native or exotic bromeliads was sampled for immature mosquitoes. Culex biscaynensis was the most commonly collected mosquito from exotic bromeliads at study sites in southeastern Miami-Dade County, whereas at nearby sites with native bromeliads, immature Wyeomyia mitchellii were more abundant than immature Culex biscaynensis. Aquatic habitat size and persistence may be important factors favoring Culex biscaynensis in exotic bromeliads. Leaf axils of exotic bromeliads had a greater water-holding capacity than those of the native bromeliads; and because the exotic bromeliads were located on the ground usually near lawn watering sprinklers, their aquatic habitats may persist longer than those of the native, epiphytic bromeliads that received only rainfall. In the exotic bromeliads, the frequency of occurrence of Culex biscaynensis was similar in tree-shaded and in open-sunlit areas. The distribution of Culex biscaynensis currently is limited to Miami-Dade County, and at sites in other south Florida counties, Wyeomyia spp. were the dominant mosquitoes in collections from exotic bromeliads. Aedes aegypti, Aedes albopictus and Culex quinquefasciatus were occasionally found in exotic bromeliads, usually in low numbers; however, these mosquitoes were not collected from native bromeliads.

The GABA(A) receptor system provides the major inhibitory control in the CNS, with the alpha 1 beta 2 gamma 2 subunit combination being the most abundant and widely distributed form of the receptor. The alpha1 subunit knock-out (alpha1 KO) mice had a surprisingly mild overt phenotype, despite having lost approximately 60% of all GABA(A) receptors. The alpha1 KO mice had normal spontaneous locomotor activity, but were more sensitive to the sedating/ataxic effects of diazepam than wildtype (WT) mice. Pharmacological modulation of dopamine and N-methyl-D-aspartate (NMDA) receptors also produced altered responses in alpha1 KO mice compared with WT mice. As expected, the NMDA receptor antagonist MK801, amphetamine and cocaine increased locomotor activity in WT mice. Although MK801 increased locomotor activity in alpha1 KO mice, amphetamine and cocaine induced stereotypy not hyperlocomotion. Binding studies showed no gross changes in the total number of D1, D2 or NMDA receptors. Furthermore, pre-pulse inhibition of acoustic startle and the effects of cocaine in conditioned place preference were similar in both alpha1 KO and WT mice, indicating selective rather that global changes in response to dopaminergic agents. These data demonstrate subtle changes in behaviours mediated by neurotransmitters other than GABA in alpha1 KO mice and suggest that compensation may have occurred beyond the GABAergic system.

We tested the hypothesis that differences in temperature and desiccation tolerances of eggs of the container-dwelling mosquitoes Aedes albopictus and Aedes aegypti influence whether invading A. albopictus coexist with or exclude A. aegypti in Florida. In the laboratory, egg mortality through 30 days for A. albopictus was strongly temperature and humidity dependent, with low humidity and high temperature producing greatest mortality. In contrast, mortality through 30 days and through 60 days for A. aegypti was very low and independent of temperature and humidity. Mortality through 90 days for A. aegypti showed significant effects of both temperature and humidity. In the field, the proportion of vases occupied by A. albopictus was significantly lower at four of six sites at the start of the wet season (after a dry period) versus well into the wet season (after containers had held water for weeks). The proportion of vases occupied by A. aegypti was independent of when during the wet season vases were sampled. These results imply that dry periods cause disproportionately greater mortality of A. albopictus eggs compared to A. aegypti eggs. Container occupancy at tire and cemetery sites was significantly related to two principal components derived from longterm average climate data. Occupancy of containers by A. albopictus was greatest at cool sites with little or no dry season, and decreased significantly with increasing mean temperature and increasing number of dry months. In contrast, occupancy of containers by A. aegypti was lowest at cool sites with little or no dry season, and increased significantly with increasing mean temperature and increasing dry season length, and decreased significantly with total precipitation and number of wet months. We suggest that local coexistence of these species is possible because warm, dry climates favor A. aegypti and alleviate effects of competition from A. albopictus via differential mortality of A. albopictus eggs.

The female, male, male genitalia, pupa, and larva of Culex biscaynensis, a new species in the Bisulcatus Group of subgenus Micraedes, are described and illustrated. The species, which is presently known only from south Florida, United States, is most similar to Culex (Micraedes) antillummagnorum Dyar.

Aedes albopictus was collected from water-holding rock holes along 3 streams in Georgia and 1 in South Carolina. To compare the occurrence of Ae. albopictus and Aedes atropalpus, rock holes were sampled for immature Aedes at 2 sites where there were numerous rock holes harboring mosquitoes. At 1 of these sites, tree holes and various types of artificial containers were also sampled for immature Aedes. At both sites, immature Ae. albopictus occurred in rock holes much less frequently than the rock-pool specialist, Aedes atropalpus. Moreover, the distribution of Ae. albopictus was limited to rock holes in less flood prone locations, whereas Ae. atropalpus was often a common mosquito even in rock holes that were among the most susceptible to flooding by rising stream levels. By contrast. Ae. albopictus was frequently found in the samples from tree holes and artificial containers. Thus, it appears that riverine rock holes that are flooded frequently may be, at best, marginal habitats for Ae. albopictus.

Immatures of a Culex (Micraedes) sp. were collected from bromeliads at 6 sites in Dade County, FL. This discovery represents the first time a member of this subgenus has been detected in the continental United States. The Cx (Micraedes) sp. was found in both native and exotic bromeliads, and at some sites this Culex occurred in these plants as frequently as Wyeomyia spp.

Waste tires and other types of artificial containers were sampled for immature Aedes to monitor changes in the occurrence of Aedes aegypti (L.) and Aedes albopictus (Skuse) in Florida. The initial invasion and spread of Ae. albopictus in Florida occurred in the northern part of Florida. Throughout this region, major declines in the abundance of Ae. aegypti have been associated with the expansion of Ae. albopictus in both urban and rural areas. Generally, the same results have occurred in central Florida, but at some urban locations Ae. aegypti has remained a common mosquito long after the arrival of Ae. albopictus. In southeastern Florida, Ae. aegypti is currently the dominant container-inhabiting Aedes in urban areas, whereas sites dominated by Ae. albopictus are in rural settings or in undeveloped tracts of land within urban or suburban areas. At some locations, immature Ae. albopictus were found in the same containers with another exotic mosquito, Ae. bahamensis Berlin. The persistence of thriving Ae. aegypti populations in urban areas of southern Florida indicates that Ae. albopictus might not become the dominant container Aedes in these habitats, at least not to the extent that it has in the northern part of the state.

Under laboratory conditions, most colony and field-collected Aedes bahamensis Berlin females developed eggs autogenously when they had access to sugar. However, significantly fewer starved females were autogenous, and they produced smaller egg clutches. Autogenous fecundity covaried with wing length, and smaller females generally failed to express autogeny. Mating had no effect on the maturation of the initial egg clutch. Most starved, nulliparous females blood fed from a restrained host. At a south Florida field site, both parous and nulliparous Ae. bahamensis were captured with a power aspirator, but concurrent sampling with dry ice-baited, light traps collected only parous females. Host-seeking females, taken either in chicken-baited traps or as they attempted to blood feed on humans, were also parous, with a single exception. Thus, at this field site, Ae. bahamensis females normally delayed blood feeding until after their first oviposition. Whether or not Ae. bahamensis females in other south Florida populations show a similar gonotrophic pattern probably will depend upon the availability of sugar sources and conditions in the mosquito's aquatic habitat that affect adult size.

Water-holding stone vases were sampled in 4 central Florida cemeteries to compare the prevalence of mosquitoes in containers with and without metallic liners. Overall, immature mosquitoes were found in more than 60% of the vases lacking liners and in more than 50% of the vases with aluminum liners. Significantly fewer vases with copper liners were positive for mosquitoes. High mortality and a lack of development were observed in a field test involving the introduction of Aedes aegypti larvae into stone vases with copper liners.

Aedes albopictus has been found in 53 of the 67 Florida counties. The initial discoveries in 11 of these counties were made in cemeteries. At several locations, Ae. albopictus became well-established in cemeteries before appearing in nearby accumulations of waste tires. The recycling of plastic floral baskets may be aiding the spread of Ae. albopictus. Mosquitoes were commonly found in all types of flower-holding containers in cemeteries, except bronze vases. In the laboratory, most Aedes aegypti eggs laid in bronze vases hatched, but larvae subsequently died. The spread of Ae. albopictus in cemeteries seems to occur at the expense of Ae. aegypti populations. At one cemetery immature Ae. albopictus and Ae. aegypti were found in about 70% of the Aedes-positive containers at the start of a monitoring program. In subsequent collections from this site, Ae. albopictus was found in nearly all Aedes-positive containers, whereas there was a progressive decrease in containers with Ae. aegypti. This trend did not appear to be the result of any seasonal pattern because in a nearby cemetery where Ae. albopictus was absent, Ae. aegypti did not show a similar decline. Limiting flower-holding containers to those with drain holes or to bronze vases would greatly limit mosquito production.

1. Most of the female crabhole mosquitoes Deinocerites cancer Theobald entering bait traps had undeveloped ovaries. 2. Nearly half of the D. cancer females that were captured in bait traps, but denied blood, were gravid following a 1 week holding period; they developed relatively small egg clutches autogenously (mean = 7.4 eggs per gravid female). 3. Although both parous and nulliparous D. cancer females were captured exiting from crabholes, only parous females were attracted to and collected in bait traps. 4. Much larger egg clutches (mean = 41.8 eggs per female) were produced anautogenously by mosquitoes that blood-fed on chickens. 5. All D. cancer females from field collected pupae developed eggs autogenously when allowed to mate and sugar feed in the laboratory. These mosquitoes produced an initial egg clutch with a mean size equivalent to that found in blood-fed, parous mosquitoes from bait traps. 6. In the field, mating and sugar feeding rather than blood-feeding seem to stimulate production of the initial egg clutch. 7. D. cancer blood-feeding appears to be delayed until after the first egg clutch has been laid; some parous crabhole mosquitoes are facultative blood feeders and can produce an egg clutch either with or without a blood meal.

A male-dependent stenogamous condition was found in a strain of Aedes taeniorhynchus that was derived from a field collection taken near Puerto Peñasco, Mexico. Mating occurred readily in this strain, even when the adults were confined in 8-dram glass shell vials. Under such conditions, mating also occurred in interstrain crosses involving Puerto Peñasco males with females from Florida strains of Ae. taeniorhynchus, but not in reciprocal crosses. For males of the Puerto Peñasco strain, flight did not appear to be a prerequisite for mating.

Seasonal and habitat influences on the egg-laying activity of four species of Culex were compared in south Florida using jar- and vat-type oviposition traps. Egg rafts of Culex nigripalpus Theobald, Cx. quinquefasciatus Say, and Cx. salinarius Coquillett were collected in every month of the year, but rafts of Cx. restuans Theobald were absent during spring and summer. Cx. nigripalpus was the dominant species in the summer and fall, and Cx. quinquefasciatus and Cx. salinarius peaked during the winter and spring. Cx. restuans oviposited most rafts in the fall (98.4%). Most Cx. nigripalpus egg rafts were laid in vats (88.5%), and most Cx. quinquefasciatus egg rafts were deposited in jars (58.7%). Fewer Cx. quinquefasciatus rafts were found in a wooded area (32.4%) with a dense undergrowth than in a more open area (67.6%), but Cx. nigripalpus showed no ovipositional preference between these two habitats. The number of rafts oviposited by all species was reduced during periods of rainfall.

Pupae and fourth instar larvae of a southern (30°N, Alabama, USA) population of Wyeomyia smithii Coq. (Diptera: Culicidae) were collected from pitcher plants. Adults which emerged were maintained without food then dissected to determine their egg clutch size. Among females which matured eggs, fecundities were negatively correlated with larval densities in individual pitchers. The mean autogenous fecundity of the overwintering generation did not differ from a summer sample. Adults unable to mature eggs comprised 6-39% of samples, depending on whether collected as pupae or fourth instar larvae. Fecundity was negatively correlated with time to adult eclosion among larvae maintained on unrenewed pitcher contents in the laboratory.Cohorts from this population were reared in artificial containers from egg hatch to adulthood at a single density and a superior or inferior diet. On the superior larval diet, all females survived to reproductive age, and all but one (>99%) produced eggs autogenously. On the inferior diet, survivorship to adult eclosion was significantly less, a high proportion of females died before reaching reproductive age, and only 19% of survivors matured eggs without blood. Protracted larval development induced by the inferior diet did not influence the probability of autogeny among females that survived to reproductive maturity.The relationship between larval environment and reproductive strategies is contrasted across the geographic range of W. smithii. Bloodfeeding occurs among southern populations where density dependent constraints on preimaginal growth are constantly severe. The loss of hematophagy among northern populations may have been facilitated by periods of density independent larval growth.

The exotic mosquito, Aedes bahamensis, is now well-established in south Florida, where it is widely distributed throughout Dade and southern Broward Counties in both urban and rural areas east of the Everglades. When discarded automobile tires were sampled in areas near human habitation, larvae and pupae of Ae. bahamensis were frequently found in association with immature Ae. aegypti. Elsewhere, however, Ae. bahamensis generally occurred in the absence of Ae. aegypti. The persistence of Ae. bahamensis populations at specific sites was documented in egg collections from ovitraps and in larval samples from the water retained in discarded tires.

Wild poplulations of Aedes taeniorhynchus were polymorphic for the diets required for ovarian development. In Aedes taeniorhynchus populations from mangrove swamps, most females possessed the capacity to produce eggs on a blood-free diet. But where the grassy salt marsh was the mosquito's principal habitat,most females lacked this capacity. Both kinds of females could utiliZe a blood meal for egg production.