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A variety of refugia were offered to different instars of brown recluse spiders, Loxosceles reclusa Gertsch and Mulaik, and a South American recluse spider, L. laeta (Nicolet), to determine whether they preferred certain types of refugia spaces. Variables included (1) crevice widths ranging from 3.2 to 21 mm, (2) horizontal and vertical orientations, and (3) new refugia or refugia that had silk deposited by a previous conspecific resident. An additional 30-d assay with similar-sized refugia studied each species' propensity for site fidelity or movement among refugia. L. reclusa preferred crevice widthsor = 9 mm with no correlation of body size to crevice width, whereas L. laeta preferred crevice sizesor = 6.4 mm with a marginally significant correlation between crevice width and body size. Both species preferred (1) vertical instead of horizontal-oriented refugia and (2) refugia with conspecific silk compared with previously uninhabited refugia. There was no significant difference between the species in their propensity to move among refugia in the 30-d trial; however, both species had individuals that were always found in the same refugium for the entire assay and individuals changing refugia every 2-3 d. The propensity to switch refugia was not affected by the degree of starvation for the period tested as was initially hypothesized. The possible implications of this research toward developing novel control measures for Loxosceles spiders are discussed.

Using natural venom collected from the red imported fire ant, Solenopsis invicta Buren, we determined the dose of venom necessary to kill 50% of the workers (LD50) of Argentine ants, Linepithema humile (Mayr), and several other ant species that the fire ant may encounter in California. Of the species tested, the Argentine ant was most susceptible to the venom. On a weight-adjusted basis the red imported fire ant was 330 times more resistant to the venom than the Argentine ant. In addition, the native southern fire ant, Solenopsis xyloni McCook, was significantly more susceptible to the venom than S. invicta. Formica perpilosa Wheeler was most resistant to the venom when the LD50 was not adjusted for weight, requiring a dose 684 times higher than that of the Argentine ant. When we tested synthetic venom (solenopsin A, which is the main component of S. xyloni venom) against the Argentine ant, the LD50 value was unchanged. However, both S. invicta and S. xyloni were ≈6 times more susceptible to the synthetic compound than to natural venom. Therefore, S. invicta venom is less toxic to fire ants while being just as toxic to Argentine ants as the simpler, more primitive venom of S. xyloni. Fire ant gaster flagging and venom dabbing applies enough venom to the Argentine ant to be lethal and may help explain the superior interference competition shown by the red imported fire ant.

Western subterranean termites, Reticulitermes Hesperus Banks, did not tunnel in soil with particle sizes ranging from 0.84 to 2.36 mm. Instead, they tunneled at equal rates in soils with particle sizes ranging from 0.15 mm. The latter range of soils was treated with termiticides in the study. In continuous-exposure studies in which termites were placed on soil treated at ≥ 50 ppm with termiticide, bifenthrin, cypermethrin, or permethrin had the greatest activity. Soil treated with chlordane, permethrin ( 50 ppm permethrin. Fenvalerate (< 100 ppm) and isofenphos formulations were the least active treatments. In tunneling studies, termites did not tunnel into soil treated with formulations of bifenthrin or cypermethrin, even at the lowest concentration tested. No tunneling occurred in soil treated with formulated chlordane, chlorpyrifos, fenvalerate, isofenphos, or permethrin at concentrations ≥ 50 ppm. Mortality from the tunneling activities was greatest in tubes filled with soil treated with formulated bifenthrin and chlorpyrifos. Even though termites tunneled only in the untreated soilbelow the soiltreated with chlordane, chlorpyrifos, fenvalerate, isofenphos, or permethrin formulations at concentrations ≥50 ppm, mortality and sublethal effects were observed. Insecticide probably diffused from treated areas to untreated areas in concentrations high enough to produce kill or affect behavior.

Laboratory studies were done to evaluate the repellency and efficacy of 25 insecticides against foraging workers of the Argentine ant, Iridomyrmex humilis (Mayr). The trail pheromone of I. humilis, cis-9 hexadecenal, was used to induce trailing and movement through sections of glass tubing treated with insecticides. General repellency of formulations was ranked as granular < emulsifiable concentrate < dust < wettable powder. As the repellency of the insecticide increased, mortality increased. Potential field efficacy of 25 insecticides as barrier treatments is discussed.

Four different termite control strategies consisting of two soil treatments with cypermethrin and fipronil and two bait treatments with hexaflumuron and sulfluramid were evaluated for their efficacy and potential for controlling the invasive eastern subterranean termite, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae), in Quillota and Valparaiso, Chile. Monitoring stations were installed at all sites to measure the overall termite activity next to and at distances up to 30 m away from infested structures, most being 3-5 m. Foraging activity was extremely seasonal with the maximum consumption rates occurring from January to April. Termite foraging activity was low from July to September. After treatments in January 2003, there was a significant decrease in wood consumption, percentage of active stations, and numbers of termites in traps for the first 6 mo with hexaflumuron baits. No significant change in R. flavipes foraging activity was observed on wood consumption and percentage of active stations for sulfluramid bait or cypermethrin and fipronil soils treatments. The seasonal pattern of foraging activity remained unchanged for all treatments in 2004 and 2005, except structures baited with hexaflumuron. Feeding activity at the monitors in the area surrounding the hexaflumuron baits declined to 0 after January 2004. Alate flights occurred in approximately 38% of the structures treated with cypermethrin and sulfluramid bait in 2003 and in approximately 40% of the structures treated with cypermethrin, fipronil, and sulfluramid bait in 2004. Sulfluramid baits and cypermethrin soil treatments did not have any impact within a 15-m radius of the structures. Soils treatments of fipronil and cypermethrin prevented termites access in 75% of the homes. The number of active monitoring stations only declined within 2 m of the fipronil-treated zone. Hexaflumuron exhibited a reduction in activity for at least a 15-m radius.

The potential horizontal transfer ofnonrepellent termiticides has become an important paradigm to control termites in recent years. In this study, 14C-radiolabeled fipronil was used in a series of laboratory experiments to demonstrate the extent and ability of termites to transfer lethal amounts of fipronil to unexposed nestmates. Fipronil is an active and nonrepellent termiticide against western subterranean termites, Reticulitermes hesperus Banks, on sand at relevant doses. It exhibited delayed toxicity with the lowest LD50 approximately 0.2 ng/termite expressed between day 4 and 7. Both continuous and brief exposures to fipronil-treated sand seriously impaired the termite's ability to move and respond to a dodecatrienol trail, limiting potential horizontal transfer. In tunneling studies, fipronil prevented termite tunneling at concentrations as low as 0.5 ppm and was nonrepellent even at 500 ppm. Greater than 90% mortality was recorded by day 7 with concentrations ranging from 0.5 to 500 ppm. There was a linear relationship between the time of exposure and uptake of [14C]fipronil when termites were continuously exposed to 0.5, 1.0, and 5.0 ppm for 24 h. However, uptake discontinued when the termites were immobilized. Maximum transfer of fipronil from donors to recipients occurred within the first 24 h. Fipronil was transferred by body contact and trophallaxis did not play a major role in horizontal transfer. In successive transfer studies, there was not enough fipronil on recipients for them to serve as secondary donors and kill other termites. In a linear arena study, there was an inverse relationship between the amount offipronil on dead termites and their distance from the treated zone. Maximum mortality was observed within 1.5 m from the treated zone. Results in our laboratory studies suggest that horizontal transfer was not a major factor contributing to the efficacy of fipronil in the field.

A flea larval bioassay was developed by an international team of scientists to monitor the susceptibility of fleas (Ctenocephalides felis) to imidacloprid (Advantage, Bayer HealthCare). The assay was validated using laboratory and field isolates of C. felis. Flea eggs representing different field isolates of C. felis were collected by veterinarians in the United States, United Kingdom, and Germany. Of the 972 flea isolates obtained during the 5-year study, 768 contained sufficient numbers of eggs to conduct the larval bioassay. Greater than 5% survival occurred for only six of the field isolates evaluated. Further evaluation and analysis of these isolates demonstrated that they did not differ significantly in their susceptibility to imidacloprid from the reference strains used to develop the assay. Collections of field flea isolates will continue in an attempt to detect and document any change in the susceptibility of field flea populations to imidacloprid.

Trail pheromones mediate communication among western subterranean termites, Reticulitermes hesperus Banks. Repetitive passages ofor=28 termites were required to establish a pheromone trail and trails needed to be reinforced because they lasted48 hr. The minimal threshold concentration for inducing responses from termite workers and secondary reproductives was between 0.01 and 0.1 fg/cm of (3Z,6Z,8E)-dodecatrien-1-ol (henceforth, dodecatrienol). Workers showed optimal trail-following behavior to dodecatrienol at a concentration of 10 fg/cm. Trails with concentrations10 pg/cm were repellent to workers. Workers did not detect pheromone gradients, responding equally to increasing or decreasing gradients of dodecatrienol, and termite workers were not able to differentiate between different concentrations of dodecatrienol. Termites preferred dodecatrienol trails to 2-phenoxyethanol trails. Antennae played a key role in trail pheromone perception. Dodecatrienol acted as an arrestant for worker termites (10 fg/cm2) and male alates (5 ng/cm2), whereas sternal gland extracts from females attracted male alates. Workers and alates, upon contact with filter paper disks treated with higher doses (10 fg/cm2 and 5 ng/cm2, respectively) of dodecatrienol, were highly excited (increased antennation and palpation) and repeatedly returned to the treated disks. Dodecatrienol did not act as a phagostimulant when offered on a paper towel disk. Reticulitermes hesperus is highly responsive to dodecatrienol, and it may play an important role in orientation of workers and alates.

Western subterranean termite, Reticulitermes hesperus (Banks), prefers various mono-, di-, and trisaccharides, total feeding being the greatest on paper disks treated with 5% ribose followed by 3% xylose, 2% maltose, 2% fructose, 2% arabinose, and 2% ribose. In multiple choice tests, termites were not able to discriminate between 2% ribose, 2% fructose, 2% xylose, and 2% maltose. Termites readily take up [14C] sucrose in feeding studies. Most of the sucrose is used as an energy source for respiration (89.2%), a very small proportion remains within the termite (9.3%), and an even smaller amount is excreted as solid waste (1.5%). The amount of 14C label transferred to other colony members via trophallaxis, body contact, or grooming is small and directly dependent upon the time and numbers of donors and recipients. At day 15 postmixing, the percentage of transfer was highest, 14.4 and 15.1% for both 1:1 and 2:1 donor to recipient mixing ratios, respectively. The mean amount of labeled 14C received by recipients increased from seven disintegrations per minute (dpm) on day 2 to 30 dpm on day 15 for 1:1. Overall mean radioactivity recovered from recipient termites when mixed with donor termites at 1:1 ratio (20 dpm) was significantly less than (28 dpm) when mixed with donor termites at 2:1 ratio. Sugars act as phagostimulants to the termites at concentrations much higher to those that termites naturally encounter in wood. Termites readily metabolize carbohydrates such as sucrose, and thus their use in bait matrices may increase consumption and retention at bait stations.

The susceptibility of four laboratory strains of cat fleas, Ctenocephalides felis (Bouche), to imidacloprid was determined by three different laboratories, by using a standardized bioassay protocol. The probit lines generated by the different laboratories were very similar, with LC50 values ranging from 0.32 to 0.81 ppm. Based on these data, a diagnostic dose (DD) of 3 ppm imidacloprid in larval rearing media was provisionally identified for detecting shifts in tolerance, possibly as a consequence of incipient imidacloprid resistance. None of the larvae from the susceptible laboratory strains survived the DD. Eighteen field-collected isolates were evaluated for their susceptibility to imidacloprid and to validate a DD of 3 ppm. Probit lines from 18 field-collected isolates were very similar, with LC50 values ranging from 0.14 to 1.52 ppm. When exposed to the DD, between 3 and 10% of the exposed larvae emerged as adults from only three of the 18 isolates. All other field isolates gave 100% mortality at the DD. Under the criteria established (>5% survivorship at 3 ppm), two isolates would be established on mammalian hosts and more extensive tests conducted to exclude or confirm the presence of resistance. The DD of 3 ppm is robust enough to eliminate most of the susceptible isolates collected until today, yet low enough to identify possible isolates for further testing.

Cat fleas are the most important ectoparasite of cats and dogs worldwide. During the past ten years, topical and oral applications of insecticides such as fipronil, imidacloprid, lufenuron and, most recently, selamectin have revolutionized cat-flea control. Recent studies show that these therapies eliminate the need to treat indoor and outdoor environments, and their use markedly reduces the severity and prevalence of flea allergic dermatitis. Surveys have yet to reveal the development of insecticide resistance to these chemical compounds. Extending the longevity of these effective host-targeted therapies should be a major goal of the veterinary community.

Boric acid, imidacloprid, and thiamethoxam in sucrose aqueous baits had different delayed toxicities to worker Argentine ants, Linepithema humile (Mayr). The concentrations required to produce an LT50 (time required to produce 50% mortality) within 1-4 d were 3.63-0.55% boric acid, 9.2 x 10(-3) to 7.1 x 10(-4)% imidacloprid, and 3 x 10(-4) to 2 x 10(-5)% thiamethoxam. The three toxicants were not repellent. Other laboratory trials showed that 1% boric acid, 5 x 10(-4) to 5 x 10(-3)% imidacloprid, and 1 x 10(-5) to 1 x 10(-3)% thiamethoxam had delayed toxic effects, whereas 0.5% boric acid and5 x 10(-3)% imidacloprid did not. Baits that provided an LT50 between days 1 and 4 were considered to have delayed toxic effects. The utility of aqueous sucrose baits and toxicants soluble in such systems and the negative impact of fast-acting toxicants on trail following, recruitment, trophallaxis, and control of Argentine ants are discussed.

Two insecticides, fipronil and imidacloprid, were evaluated for efficacy and longevity against Oropsylla montana (Baker), the most important vector of plague in California. Wild-caught California ground squirrels, Spermophilus beecheyi (Richardson), were individually housed in the laboratory to serve as natural hosts to O. montana and for on-animal insecticide trials. Several concentrations oftechnical grade fipronil and imidacloprid in acetone were applied to samples of clean rodent bedding to determine residual activity and longevity against fleas. Immature and adult cat fleas, Ctenocephalides felis (Bouche), were used as representative fleas for periodic assays in place of less fecund O. montana. Toxicity of treated bedding did not decrease significantly for 1 yr at all applied concentrations. Fipronil provided 100% kill for at least 1 yr at > or = 100 ppm, whereas imidacloprid required 10,000 ppm for similar performance. Laboratory squirrels were treated with topical formulations of fipronil (Frontline Top Spot) and imidacloprid (Advantage Flea Adulticide) at a dosage rate of 15 mg/kg and evaluated for residual activity every 2 wk against adult O. montana. Residual activity was determined by percent recovery of O. montana adults released on treated and untreated animals after 48 h. Frontline provided 100% kill of adult fleas for at least 10 wk, and up to 26 wk on one animal. Advantage failed to provide 100% kill of adult fleas at 2 wk, with complete loss of efficacy by week 6. Concurrent assays with bedding samples from squirrel nest boxes showed negligible toxicity transfer from treated animals to nest bedding.

Strategies for controlling cat fleas, Ctenocephalides felis felis (Bouche), have undergone dramatic changes in the past 5 yr. With the advent of on-animal treatments with residual activity the potential for the development of insecticide resistance increases. A larval bioassay was developed to determine the baseline susceptibility of field-collected strains of cat fleas to imidacloprid. All four laboratory strains tested showed a similar level of susceptibility to imidacloprid. Advantages of this bioassay are that smaller numbers of fleas are required because flea eggs are collected for the test. Insect growth regulators and other novel insecticides can also be evaluated. Using a discriminating dose, the detection of reduced susceptibility in field strains can be determined with as few as 40 eggs.

This chapter summarizes the various use patterns of insecticides used in and around structures to control the major urban arthropods and insects. The widespread use and need for pest management in and around structures can be directly attributed to the dislike of insects and arthropods by urban residents. Some insects such as termites and wood-destroying beetles pose a serious economic threat to structures and a few, such as cockroaches, fleas, mosquitoes, and ticks, may present a real medical or veterinary problem. However, many urban insects may be classified as occasional intruders and nuisance pests. Pyrethroid insecticides will continue to be used, but their effectiveness against German cockroaches will continue to decline because of insecticide resistance. In addition, the list of available fumigants will also decrease in the future. The popularity of baits will continue, stimulating new avenues of research dealing with the behavior and ecology of structural insect pests.

Cat fleas, Ctenocephalides felis (Bouché), were reared at different temperatures to examine further the effects on egg-to-adult development and emergence of adults from cocoons. Three different temperatures (26.7, 21.1, and 15.5 degrees C) were used to rear fleas. Emergence of adults from cocoons was monitored using 2 experimental designs-cocoons maintained in groups and cocoons individually isolated. At cooler temperatures, cocoons kept in groups had a higher incidence of late-emerging adults than did individual cocoons. At 15.5 degrees C, adults continued to emerge from grouped cocoons up to 80 d after all had emerged from individual cocoons. Developmental time of prepupae and pupae was determined by inhibiting cocoon formation of late 3rd instars. Male prepupae and pupae developed approximately 20% slower than did females. Comparisons between emergence of adults from cocoons and from naked pupae indicate that a large percentage of adults emerge from cocoons soon after molting. The possible association of developmental temperatures and emergence from cocoons with overwintering populations is discussed.

Control failures and recurrences of infestation of dogs, cats and their home environment with the cat flea, Ctenocephalides felis felis are common. Attempts to control these infestations are often impaired by an inadequate understanding of the interaction of the cat flea with its hosts and environment. This review presents information on the medical and veterinary importance of the cat flea and discusses recent information on the environmental and host factors that effect its development and survival. Additionally, information is presented on the use and effectiveness of various insecticides and insect growth regulators against the four life stages.

Topical application (LD) and time-mortality response (LT) methods were used to determine resistance levels of field-collected strains of the German cockroach, Blattella germanica (L.). LD50s for chlorpyrifos were determined for seven strams. LT50s and LT90s with eight insecticides were determined for another three strains. Resistance ratios (RR) of >10 to chlorpyrifos (LD50) were directly related to a significant decrease in activity in Ebeling choice-box tests. Using the LT method, the three field-collected strains were shown to possess zero to moderate resistance at the RR50 level (0.9–5.3) to organophosphates, moderate to high resistance to (1.4–>21.0) to carbamates, moderate to high resistance (4.3–20) to cypermethrin, and high resistance (>17–>35) to synergized pyrethrins. When the three field-collected strains were tested in choice boxes, RR50s of 1.2–2.2 for chlorpyrifos and 2.5–5.3 for diazinon directly related to significantly lower efficacy. Low-level propoxur resistance (RR50 of 1.4–2.3) also reduced choice-box efficacy, but an RR50 of 0.9–1.3 for acephate did not reduce its performance. Cypermethrin deposits used in choice tests killed cockroaches exhibiting RR50s as high as 20 in the lethal time test, perhaps because resistance mechanisms could not detoxify the exceptional activity of the active ingredient formulated as a wettable powder. Because they were repellent, residual deposits of pyrethrins resulted in poor efficacy in choice tests with either susceptible or field-collected strains. Strains with low-level physiological resistance as measured by the time-mortality response method survived insecticide exposure in choice-box tests to certain organophosphate and carbamate insecticides, indicating that these compounds would not be effective in the field.

Baits, dusts, and aqueous sprays were applied to sewer shafts to control American cockroaches, Periplaneta americana (L). Boric acid and hydramethylnon baits failed to provide consistent control because of problems with mold on the baits and because large populations of cockroaches depleted the bait. Bendiocarb, boric acid powder, and a powder mixture of silica gel + synergized pyrethrins provided excellent control for at least 1 mo, but cockroaches reinfested treated shafts within 3-6 mo. Treatments made in the fall when adult cockroach populations were lowest (about 26%) provided best results. Aqueous sprays of wettable powder chlorpyrifos and microencapsulated diazinon provided outstanding control for at least 9 mo. Microencapsulated and emulsifiable concentrate chlorpyrifos sprays provided greater than 94% reductions for a year.

Infestations of this introduced pest have spread to at least 17 locations in three California counties. Localized control may be possible by surveying for infestations, inspecting cargo vehicles, applying chemicals, and trapping.

1. 1. Cuticular permeability (CP) and critical thermal maxima (CTM) were determined for ten cockroach species representing three families. 2. 2. The CP ranged from 53.7 μg/cm2/hr/mm Hg for Periplaneta americana to 14.3 for Leucophaea maderae. 3. 3. CTM values were between 51.4°C for Supella longipalpa and 47.6°C for L. maderae. 4. 4. Initial water content ranged from 62.7 to 71.8%, and was distinct for several species. Per cent of total body water lost as a function of time is presented as an alternative method of examining water loss. 5. 5. CP was generally related to habitat humidity whereas CTM was related to habitat temperature. There was no association between CP and CTM. 6. 6. CP was significantly greater in blattid species indicating reduced permeability may be an advanced derived character in the Blattellidae and Blaberidae. CTM does not appear to be associated with phylogeny.

Fecundity and longevity of the adult cat flea, Ctenocephalides felis felis , was studied with adult fleas confined inside microcells compressed to the necks of cats. Egg production began 2 days after the 1st blood meal and reached maximum levels by the 4th day. Generally only ½ of the ovarioles contained mature oocytes, with a mode of 6 and a maximum of 13 eggs contained in the abdomen. An average of 13.5 eggs/day/flea was obtained from 10 individual females, with a maximum average egg production of 22.3 eggs/day. The average total production of an individual flea over her life-span was 158.4 eggs, with 432 eggs the maximum observed. Fecundity was significantly higher in microcells containing a single female flea than in cells with 4 or more females. On-host longevity of female fleas ($\bar x$ = 11.2 days) was significantly longer than that of males ($\bar x$ = 7.2 days).

Visual and thermal cues were the primary stimuli responsible for the orientation and attraction of the cat flea, Ctenocephalides felis felis (Bouche), to sticky cylindrical targets. Postpupal age was also important. Contrast of a moving dark cylinder against a light backdrop was visually attractive to the fleas. No visual orientation was demonstrated under red light. Increasing the complexity of patterns on the target did not increase its attractiveness. Orientation and attraction to a stationary heated target was demonstrated, but required the additional stimulation of air movements to evoke a directed jump. Light, CO2, and air currents stimulated locomotion.

Soldier defensive secretions were analyzed by GC/MS in eight spatially separated groups of Amitermes wheeleri collected in Arizona and California. Eleven sesquiterpenoids, four of known structure, were isolated. Quantitative and qualitative differences among the groups of termites were extensive; composition of the defensive secretions among colonies varied from one to six components. Intraspecific differences between pairs of sympatric colonies at six sites were much less pronounced. The variability found in A. wheeleri suggests that soldier defensive secretions in the genus Amiterines are not reliable markers for interspecific systematic comparisons.

A categorized bibliography of the smokybrown cockroach, Periplaneta fuliginosa (Serville) is presented. Categories include systematics and distribution, biology, physiology, chemical and cultural control, biological control agents, behavior, and mention only.

Nymphs of the western drywood termite,Incisitermes minor (Hagen), were tested for their feeding preferences on wood and extracts of 11 tree species. The amount of wood consumed was inversely proportional to its specific gravity, but methanol extracts of least preferred woods were also least preferred when termites were confined to paper treated with extracts. In choice tests, only paper treated with extract of wood from which the colony developed and untreated and methanol-treated controls were significantly fed upon. Ponderosa pine extract applied to Douglas fir and sugar pine significantly decreased the amount of wood consumed. Resistance to termite feeding appeared to depend on the presence of repellent chemicals in the wood.

Male sexual response inPeriplaneta americana is influenced by the presence or absence of sex pheromone, the length of time since last exposure to pheromone, the length of that exposure, and the photocycle. Females begin emission of sex pheromone 9 or more days after the molt to adult. The quantity emitted does not appear to be influenced by the photocycle. During the light phase of the photocycle, males only respond to high concentrations of pheromone. They recover quickly after brief exposures, but after prolonged exposures, a second exposure 24 h later elicited responses of lower intensity.

The effects of temperature and humidity and body water and lipid content on the cuticular water loss and permeability of the smokybrown cockroach, Periplaneta fuliginosa , were examined. Cuticular water loss (μg cm −2 h −1 ) was directly correlated to body water content and inversely related to body lipid content. Density of epicuticular lipids was not associated with water loss. Cuticular water loss and cuticular permeability (μg cm −2 h −1 mmHg −1 ) increased exponentially with temperature. There was no defined transition temperature. Cuticular water loss decreased arithmetically with increasing ambient relative humidity although calculated cuticular permeability increased exponentially. Water-vapour flux experiments with tritiated water revealed that vapour efflux was independent of relative humidity. Cuticular permeability calculations that indicate relative humidity dependency under constant temperature and variable relative humidities are therefore mathematical artifacts. Water-vapor influx, however, was dependent of relative humidity as was net flux, the vector sum of efflux and influx.

1. 1. The effects of insect maintenance at various relative humidities on tissue water distribution and water loss were examined in adult male smokybrown cockroaches, Periplaneta fuliginosa, held for seven days at 11, 32, 50, 75 or 98% r.h. 2. 2. No differences in total body water content and water content of gut, fat body, muscle or cuticle were detected among males. 3. 3. Faecal water content decreased at lower acclimation r.h. 4. 4. Cuticular permeability increased linearly with acclimation r.h. 5. 5. Mean haemolymph volume and osmolality were not affected by acclimation r.h.; however, the volume and osmolality of salivary gland secretions decreased with increasing r.h. indicating acclimation had occurred.

Aspects of the life history of fungus-infected and uninfected German cockroaches, Blattella germanica (L.), were examined. Infected adult females showed a substantial reduction in number of eggs per oothecae, number of oothecae, and production of nymphs. Infected nymphs developed asynchronously and slowly (64 d) whereas uninfected nymphs developed synchronously in ca. 38 d. Life tables and age-specific survivorship curves were obtained for infected and uninfected B. germanica to estimate their potential fecundity and growth rates. The generation time of infected B. germanica was about 20% shorter than that of uninfected populations (100.4 d). Up to 74% more female offspring per female ( mx ) were produced by uninfectedv females than infected females. Cockroaches exposed to the fungus as first instars had a net reproductive rate ( Ro ) of 0.42 and an intrinsic rate of increase ( rc ) of 0.0103 compared with 184.61 and 0.0519, respectively, for uninfected B. germanica . The yeast-like fungus (Hyphomycetes: Deuteromycotina) shows potential for management of German cockroaches.

Activities of insecticides against adult cat fleas, Ctenocephalides felis (Bouche), were broadly categorized as follows: organophosphates > carbamates = synergized pyrethrins > pyrethroids. Residues of chlorpyrifos (applied at 127 mg [AI]/m2), propetamphos (127 mg/m2), permethrin (255 mg/m2), diazinon (509 mg/m2), malathion (1,018 mg/m2), and carbaryl (1,222 mg/m2) applied to nylon carpet provided >90% kill of adult cat fleas for at least 21 d. Activities of insecticide sprays were inversely related to increased density or depth of carpet. Vacuuming or simulated wear on treated carpet did not significantly affect residual activity against fleas, but shampooing reduced activity of microencapsulated diazinon and bendiocarb by 30 and 93%, respectively. Propetamphos was not affected by carpet shampoo.

After the pupal-imaginal molt, the pre-emerged adult cat flea, Ctenocephalides felis felis (Bouche), remains quiescent inside the cocoon for varying periods of time. It has a lower respiratory demand than the emerged adult and its survival is considerably longer. Pressure and heat stimulate rapid emergence from the cocoon. In the absence of these stimuli adults emerge gradually over several weeks, depending on ambient temperature, with the length of time spent in the cocoon related to prepupal weight. This pharate stage facilitates flea-host contact by maximizing the active life span of the adult flea and minimizing nonhost-induced emergence.