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PubMed1990

Influence of fenoxycarb on German cockroach (Dictyoptera: Blattellidae) populations in public housing.

In a study examining three application rates for fenoxycarb, new interpretations of population age structure in relation to sterility levels and population reductions were used to establish important concepts in the management of German cockroaches, Blattella germanica (L.), with juvenoids. No significant differences in population reductions were noted when 0.5%, 0.25%, or 0.125% fenoxycarb was used to supplement propetamphos. However, significant differences in levels of induced sterility and in the age structure (measured as nymph-to-adult ratios) of treated populations were detected. The 0.125% rate caused lower, less consistent levels of sterility than the two higher rates, which maintained approximately 80% sterility from 4.5 mo and beyond. In addition, the 0.125% rate did not significantly reduce nymph-to-adult ratios in treated populations relative to that caused by the propetamphos alone (positive control). The two higher rates significantly reduced nymph-to-adult ratios, thereby lowering biotic potential and the capacity of a population to rebound from suppression. A relationship between the level of sterility induced by juvenoids and reductions in nymph-to-adult ratios permitted formulation of a biological action threshold for regulating treatment. This action threshold appears to be more meaningful than time intervals for scheduling retreatments in the long-term management of German cockroaches with juvenoids.

Age Factors↗
PubMed1990

Efficacy of abamectin fed to German cockroaches (Dictyoptera: Blattellidae) resistant to pyrethroids.

Ten field-collected strains of the German cockroach, Blattella germanica (L.), with varying levels of pyrethroid resistance were tested for possible cross-resistance to abamectin administered as a bait. The time-mortality method was used for comparison of response with a known susceptible strain in 10-d feeding experiments. Essentially no resistance to abamectin was found. Extensive feeding inhibition occurred after a few days, but the amount of abamectin consumed varied substantially from strain to strain. Abamectin may have considerable potential as a cockroach bait insecticide.

Animals↗
PubMed1990

Nutritional status and insecticide tolerance in German cockroaches (Orthoptera: Blattellidae).

The interrelationship of two extrinsic factors-nutrition and pesticide exposure-was studied in German cockroaches, Blattella germanica (L.). Amount of dietary protein had no effect on susceptibility of male German cockroaches to propoxur and chlorpyrifos; however, the source of protein produced significant changes in insecticide susceptibility. Increased total body lipids, carbohydrates, and uric acid may have resulted in increased tolerance to these insecticides. Three days of food or water deprivation (or both) caused significant differences in susceptibility to chlorpyrifos and propoxur.

Animal Nutritional Physiological Phenomena↗
PubMed1991

Effects of several insecticide formulations on oothecal drop and hatchability in German cockroaches (Dictyoptera: Blattellidae).

Formulations used for control of German cockroaches, Blattella germanica (L.), were investigated. The insecticides tested on gravid females were bendiocarb, chlorpyrifos, cyfluthrin, cypermethrin, fenvalerate, hydramethylnon, malathion, propetamphos, propoxur, and pyrethrins. Exposure to each insecticide increased the frequency of oothecal drop and reduced the percentage oothecal hatch. The percentage of oothecae that were dropped increased as a curvilinear function of insecticide concentration. An LD50 of propoxur to female German cockroaches resulted in the greatest oothecal drop (83.50%); fenvalerate caused the least drop (22.60%). LD50's of cypermethrin, propetamphos, and propoxur resulted in 29.60, 31.807, and 37.30% hatch from dropped oothecae, respectively. The smallest percentage hatch from retained oothecae was caused by LD50's of propoxur (1.5%) and cyfluthrin (7.70%). Retained oothecae from females treated with an LD50 of fenvalerate (68.70%) or pyrethrins (68.70%) had the greatest percentage hatch. Total percentage hatch (dropped and retained oothecae) declined exponentially as the insecticide concentration increased. An LD50 of cypermethrin limited total oothecal hatch to 24.50%, whereas LD50's of fenvalerate, malathion, and pyrethrins resulted in 53.60, 52.20, and 58.90% hatch, respectively. Mean time to oothecal hatch increased linearly with increasing insecticide concentration for all insecticides tested.

Animals↗
PubMed1991

Pyrethroid resistance and synergism in a field strain of the German cockroach (Dictyoptera: Blattellidae).

A field-collected strain of the German cockroach, Blattella germanica (L.), was highly resistant to 10 pyrethroid insecticides (cyfluthrin, cyhalothrin, cypermethrin, fenvalerate, esfenvalerate, fluvalinate, permethrin, resmethrin, sumithrin, tralomethrin) based on topical applications and comparison with a known susceptible strain. Resistance ratios ranged from 29 to 337. In general, pyrethroid compounds with an alpha-cyano functional group were more toxic than those lacking this moiety, but resistance ratios were similar for both classes of compound. The metabolic inhibitors DEF and PBO were tested for synergism in conjunction with cypermethrin (alpha-cyano) and permethrin (non alpha-cyano). Application of synergists resulted in partial elimination of resistance, suggesting that the basis of resistance involves enhanced metabolism as well as target site insensitivity. These results suggest that pyrethroid insecticides may have a very short functional life in German cockroach control unless they are used judiciously.

Animals↗
PubMed1993

Relationship between insecticide resistance and performance in choice tests of field-collected German cockroaches (Dictyoptera: Blattellidae).

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 strains. 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.

Animals↗
PubMed1994

Resistance to pyrethrins in the German cockroach: inheritance and gene-frequency estimates in field-collected populations (Dictyoptera: Blattellidae).

Pyrethrins resistance was assessed genetically in the German cockroach, Blattella germanica (L.), by conventional crossing experiments. It is inherited as a simple, autosomal, incompletely dominant, trait. By manipulating the test procedure, the susceptible homozygote was clearly identified, allowing gene frequency estimates to be made using the Hardy-Weinburg equilibrium expression. Gene frequencies were estimated for four susceptible and 16 resistant field-collected populations. Values ranged from 0.10 to 0.18 for the susceptible strains, and from 0.34 to > 0.90 for the resistant strains. Changes in gene frequency over time for several resistant strains were not significant. The results are discussed from the standpoints of their effects on cockroach control and the stability of pyrethrins resistance even during extended periods with no selection pressure.

Animals↗
PubMed1994

Harborage width preferences of German cockroach (Dictyoptera: Blattellidae) adults and nymphs.

Adults and nymphal cohorts of the German cockroach, Blattella germanica (L.), were allowed 24 h to select preferred harborage widths from eight harborages between 1.59 and 12.72 mm (increments of 1.59 mm) in both individual and combined cohort studies. In individual cohort studies, 1- and 2-wk-old nymphs significantly preferred 1.59-mm-wide harborage, with 74 and 68%, respectively; 3- and 4-wk-old nymphs significantly preferred 3.18-mm-wide harborage, with 63 and 45%, respectively; 5-wk-old nymphs selected the 4.77-mm-wide harborage; and 6-wk-old nymphs were evenly distributed in 3.18- to 9.54-mm-wide harborages. Males were in 6.36- to 12.72-mm-wide harborages. Nongravid females (81%) were in 4.77-, 6.36-, and 11.13-mm-wide harborages; gravid females (94%) preferred 4.77- and 6.36-mm-wide harborages. The percentage of nymphs outside harborages decreased as cockroach age increased from 1 to 5 wk. In combined cohort studies, preferred harborage widths for all cohorts and sexes were 6.36-7.95 mm and 11.13-12.72 mm. The percentage of nymphs outside harborages was low and constant (< 4.57%) irrespective of age or sex.

Animals↗
PubMed1994

Intra- and interspecific trappings of two sympatric peridomestic cockroaches (Dictyoptera: Blattidae).

Intra- and interspecific trappings of American, Periplaneta americana (L.), and smokybrown, P. fuliginosa (Serville), cockroaches were examined in laboratory experiments. More P. americana were caught in live traps than P. fuliginosa. Overall, more individuals were caught with a conspecific bait than with a heterospecific bait. Significantly more adult male, female, and total P. americana were caught in traps baited with a conspecific than with unbaited traps. Heterospecific nymphs were repellent to male and female P. americana. More P. americana were caught with conspecific females and nymphs as bait than with heterospecific nymphs. For P. fuliginosa, only more males were caught with a trap with a conspecific compared with an unbaited trap. Traps with nymphal P. fuliginosa caught more conspecifics than did unbaited traps or traps with heterospecific nymphs. Nymphal P. fuliginosa were repelled by nymphal P. americana. P. americana were captured more frequently and were more selective in interspecific associations than P. fuliginosa. These results partly account for differences in sampling these species in areas of sympatry and suggest that volatile semiochemicals are produced and detected by most stages of these cockroaches.

Animals↗
PubMed1998

Annonaceous acetogenins as natural pesticides: potent toxicity against insecticide-susceptible and -resistant German cockroaches (Dictyoptera: Blattellidae).

Six compounds, representing the mono-tetrahydrofuran (THF) (gigantetrocin A, annomontacin), adjacent bis-THF (asimicin, parviflorin), and nonadjacent bis-THF (sylvaticin, bullatalicin) classes of annonaceous acetogenins, were compared with technical grades of synthetic amidinohydrazone (hydramethylnon), carbamate (propoxur, bendiocarb), organophosphate (chlorpyrifos), and pyrethroid (cypermethrin) insecticides to determine their dietary toxicities to insecticide-resistant and insecticide-susceptible strains of the German cockroach, Blattella germanica (L.). Differential susceptibility occurred among B. germanica nymphs of both strains to this variety of the acetogenins and the 5 conventional synthetic insecticides. The speed of kill (LT50) values against insecticide-susceptible and insecticide-resistant 2nd and 5th instars permitted ranking of all 11 compounds. The adjacent bis-THF acetogenins showed the highest potency among the 3 acetogenin classes. The acetogenins caused high percentages of mortality and delays in development of the 5th instars of both strains. Insecticide-susceptible nymphal development was mainly affected by gigantetrocin A and annomontacin, whereas insecticide-resistant nymphal development was mainly affected by gigantetrocin A and bullatalicin. Most tested acetogenins performed better than the conventional insecticides against both stages of both strains. No growth regulation effects were caused by any of the compounds tested. Low resistance ratios were obtained for most compounds (except chlorpyrifos). Low resistance ratios values for 2nd instars ranged from 0.9 to 2.2 with the natural acetogenins and from 1.0 to 3.8 with the synthetic compounds; the 5th instars ranged from 0.2 to 3.9 with the natural acetogenins and from 0.6 to 8.0 with the synthetic compounds. Insecticidal properties and characteristics of acetogenins and the possible use of acetogenins in baits for cockroach control are discussed.

Animals↗
PubMed2003

Octopaminergic agonists for the cockroach neuronal octopamine receptor.

The compounds 1-(2,6-diethylphenyl)imidazolidine-2-thione and 2-(2,6-diethylphenyl)imidazolidine showed the almost same activity as octopamine in stimulating adenylate cyclase of cockroach thoracic nervous system among 70 octopamine agonists, suggesting that only these compounds are full octopamine agonists and other compounds are partial octopamine agonists. The quantitative structure-activity relationship of a set of 22 octopamine agonists against receptor 2 in cockroach nervous tissue, was analyzed using receptor surface modeling. Three-dimensional energetics descriptors were calculated from receptor surface model/ligand interaction and these three-dimensional descriptors were used in quantitative structure-activity relationship analysis. A receptor surface model was generated using some subset of the most active structures and the results provided useful information in the characterization and differentiation of octopaminergic receptor.

Adenylyl Cyclases↗
PubMed1990

Ovicidal activity of chitin synthesis inhibitors when fed to adult German cockroaches (Dictyoptera: Blattellidae).

Ovicidal activity was observed in four adult groups (virgin males; virgin females; newly gravid females; and inseminated, reproducing females) of the German cockroach, Blattella germanica (L.), fed the chitin synthesis inhibitors triflumuron, chlorfluazuron, hexafluron, and UC 84572 (structure not disclosed) at the LC50's and LC95's determined from fifth-stage nymphs. All compounds were active only when fed to reproducing females (including the feeding period in which the ootheca is developing). Hexafluron and triflumuron at the LC50 caused 100% inhibition of hatch in reproducing females. Chlorfluazuron and UC 84572 at the LC50 had similar ovicidal activity (45.8 and 50.0% hatch, respectively). Female German cockroaches fed the chitin synthesis inhibitors before mating and after the ootheca had protruded from the abdomen were not affected. Reproductive capabilities of males were not affected, and males did not effectively transfer the compounds to untreated females during mating.

Animals↗
PubMed1991

Sensitive developmental period of last-instar German cockroaches (Dictyoptera: Blattelidae) to fenoxycarb and hydroprene.

The sensitive developmental period of last-instar German cockroaches, Blattella germanica (L.), to topical applications (10 micrograms/microliters) of fenoxycarb and hydroprene was determined. Developmental duration of last instars treated with fenoxycarb on days 1, 3, or 6 was 9-11 d longer than the development of nymphs treated with hydroprene or acetone. In addition, fenoxycarb caused mortality in 59% of the nymphs treated on day 6. A high level of wing twisting and sterility was observed among female and male cockroaches treated with fenoxycarb or hydroprene on days 1, 3, or 6 of the last stadium. Nymphal production by adults treated with juvenoids on day 9 of the last stadium (3-4 d before eclosion) was not affected. Our findings show that the sensitive developmental period for juvenoid-induced effects in last-instar B. germanica is limited to the first half of the stadium.

Animals↗
PubMed2000

The ootheca of Mastotermes darwiniensis Froggatt (Isoptera: Mastotermitidae): homology with cockroach oothecae.

The basal termite Mastotermes darwiniensis produces an egg mass, the nature of which is controversial. The debate centres on whether it is homologous with the oothecae of mantids and cockroaches and, if so, whether its simple structure is plesiomorphic or apomorphic within the Dictyoptera. To help resolve these issues we observed primary reproductives of M. darwiniensis during oviposition and examined the morphology of the reproductive product. Oviposition is cockroach-like in that the egg mass is assembled within the vestibulum and the eggs are issued externally in pairs. The reproductive product is an ootheca of the blattarian type. A distinct, tanned outer covering is stretched over the two parallel rows of eggs. No keel is present and no calcium oxalate crystals were apparent in the outer covering. We cannot rule out the possibility that the simple structure of the ootheca is plesiomorphic within Dictyoptera. However, based on (i) apomorphies shared by Mastotermes and Blattaria, and (ii) the life habits of Isoptera, a secondary reduction is the more plausible explanation.

Animals↗
PubMed2001

Coevolution between a cockroach and its bacterial endosymbiont: a biogeographical perspective.

Cryptocercus are subsocial, xylophagous cockroaches that live in temperate forests. Like other cockroaches, Cryptocercus harbour endosymbiotic bacteria in their fat bodies. Two species of Cryptocercus occur in the palaearctic, one each in eastern Russia and south-central China. In the USA, there are five species: one in the north-west and four in the south-east. Little is known about the relationship between the Eurasian and North American Cryptocercus or the causes of the disjunct distribution. Here, a molecular phylogeny for six out of the seven Cryptocercus species and their endosymbionts is inferred in an attempt to understand the evolution and biogeography of the genus. Our analysis showed that the North American Cryptocercus are monophyletic, suggesting that a single colonization event was followed by vicariance. There was complete concordance between the host and endosymbiont phylogenetic trees. Divergence estimates based on endosymbiont DNA sequences suggested that the palaearctic and nearctic Cryptocercus diverged 70-115 million years (Myr) ago and the eastern- and western-USA species diverged 53-88 Myr ago. These divergence estimates were correlated with biogeographical events, and a hypothesis is presented to explain the current distribution of Cryptocercus. Our findings suggest that Cryptocercus has had a long evolutionary history, dating back to the Jurassic.

Animals↗
PubMed2026

Sex pheromone communication and its regulation by the sex determination pathway in cockroaches.

Sexual communication in animals orchestrates a series of interactive behaviors from locating and recognizing potential partners to courtship and final mating decisions and is thus critical for sexual reproduction and population fitness. Highly efficient communication between the sexes requires not only the production and emission of species-specific signals but also their precise detection and interpretation by the receiving individuals. Cockroaches, as one of the most evolutionarily ancient and successful group of insects, are quintessential chemical communicators that rely heavily on sex pheromones for sexual communication. They have long served as excellent model organisms in studies of chemical ecology. Although the biochemical characterization of sex pheromones in several species was largely accomplished during the last century, the past two decades have witnessed remarkable progress in understanding the molecular genetics of sex pheromone communication and its regulation, particularly driven by functional genomics. This review first provides an updated comparative survey of the pheromone components identified across distinct taxa. We then synthesize, but not limited to, recent advances in identification of key molecules controlling sex pheromone production, characterization of candidate chemosensory receptors and their neural processing pathways, and the regulatory roles of the sex determination cascade in shaping sexually dimorphic traits in both pheromone production and perception. Finally, we highlight key scientific questions that remain unsolved and propose future directions aimed at extending our mechanistic understanding of cockroach pheromone communication, as well as at developing behavior-based pest management strategies.

biosynthetic pathway↗
PubMed1990

Shared and specific allergenic and antigenic components in the two sexes of American cockroach--Periplaneta americana.

The whole body extracts (WBEs) of female and male cockroaches (Periplaneta americana; Pa) were prepared separately to study the specific and/or shared allergenic and antigenic components in the two sexes. These two extracts were skin-tested on 170 respiratory allergy patients and 52 (30.6%) of them elicited a markedly positive cutaneous reaction (2+ to 4+) to any one or both the WBEs. Of these 52 patients, 32 (61.5%) produced a 2+ to 4+ response to only one, and the remaining 20 (38.5%) to both the extracts. In female and male RASTs to Pa both the extracts produced dose-related inhibition. Using rabbit anti-Pa female serum: (1) immuno-diffusion experiments resulted in lines of identity with the two extracts, and (2) the two-dimensional immunoelectrophoresis of Pa female and Pa male WBEs elicited 12 and nine precipitin peaks, respectively. In partial purification studies, only fraction Pa(F)III (approximately 50 kD) of Pa female WBE and Pa(M)I (greater than or equal to 600 kD) and Pa(M)III (approximately 50 kD) fractions of Pa male WBE revealed significant allergen activity both on skin testing and also in RAST inhibition studies. These results provide evidence for the presence of shared as well as specific allergenic and antigenic components in the two sexes of American cockroach.

Allergens↗
PubMed1993

Isolation and in vitro translation of messenger RNA from the American cockroach.

Total RNA was extracted from the whole body of American cockroach (Periplaneta americana) using chaotropic salt guanidine isothiocyanate in the presence of 2-mercaptoethanol (2-ME). Polyadenylated mRNA was isolated by oligothymidylic acid-cellulose chromatography and mRNA was translated using a rabbit reticulocyte lysate system. The translation, as judged by the incorporation of 35S-methionine, was obtained with poly(A)+ RNA, where an approximately 9.5-fold increase in label incorporation over control was achieved. Analysis of translation products by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) in combination with autoradiography showed that many proteins with apparent molecular weights ranging from 12 to 200 kD were synthesized, and no labelled proteins were found with negative RNA control and poly(A)- RNA. Immunoprecipitation studies performed using polyclonal and monoclonal antibodies revealed that synthesized proteins of MW 90, 78, 72, 49, 45, and 26 kD corresponded with previously identified principal and major allergens of American cockroach from our laboratory. In addition, the allergenicity of the translation mixtures was also confirmed by fluoroallergosorbent test (FAST) inhibition studies with IgE antibodies of human reaginic serum pool.

Allergens↗