Insect fauna in nests of the Eurasian griffon vulture (Gyps fulvus) in Croatia

Qualitative, quantitative and trophic structure of insects found in Eurasian griffon vulture nests were analysed. A total of 249 insects belonging to six orders were found in 18 griffon vulture nests, collected in three colonies on the islands Cres and Plavnik (Adriatic Sea). Eudominant orders were beetles (64.26%) and ants (22.49%). Dermestid beetles were present in all examined nests and comprise the permanent nest fauna. Other groups of insects (cockroaches, web spinners, ants, flies, aphids) were found to occur occasionally in nests.     

The importance of host ecology in thelastomatoid (Nematoda: Oxyurida) host specificity

An experimental investigation of host specificity within the Thelastomatoidea is presented by means of a comparison of the thelastomatoids of two panesthiine cockroaches, Panesthia cribrata and P. tryoni tryoni, with those of other log-dwelling arthropods and those of leaf litter dwelling arthropods found near by. 145 log-dwelling and leaf-litter dwelling arthropods, representing adjacent ecological niches, were collected from Lamington National Park, Queensland, Australia. A high degree of thelastomatoid species sharing (19 incidences from 26 specimens) occurs between log-dwelling arthropods and the two cockroach species. No overlap in thelastomatoid fauna was observed between the log dwelling and leaf-litter dwelling groups. Our results suggest that host specificity of thelastomatoids is largely dictated by host ecology.     

Wood-feeding cockroaches as models for termite evolution (Insecta: Dictyoptera): Cryptocercus vs. Parasphaeria boleiriana

Isoptera are highly specialized cockroaches and are one of the few eusocial insect lineages. Cryptocercus cockroaches have appeared to many as ideal models for inference on the early evolution of termites, due to their possible phylogenetic relationship and several shared key attributes in life history. Recently, Pellens, Grandcolas, and colleagues have proposed the blaberid cockroach Parasphaeria boleiriana to be an alternative model for the early evolution in termites. We compare the usefulness of Cryptocercus and P. boleiriana as models for termite evolution. Cryptocercus and lower Isoptera (1) can both feed on comparatively recalcitrant wood, (2) have an obligate, rich and unique hypermastigid and oxymonadid fauna in the hindgut, (3) transfer these flagellates to the next generation by anal trophallaxis, (4) have social systems that involve long-lasting biparental care, and, finally, (5) are strongly suggested to be sister groups, so that the key attributes (1)-(4) appear to be homologous between the two taxa. On the other hand, P. boleiriana (1) feeds on soft, ephemeral wood sources, (2) shows no trace of the oxymonadid and hypermastigid hindgut fauna unique to Cryptocercus and lower Isoptera, nor does it have any other demonstrated obligate relationship with hindgut flagellates, (3) is likely to lack anal trophallaxis, (4) has only a short period of uniparental brood care, and (5) is phylogenetically remote from the Cryptocercus+Isoptera clade. These facts would argue against any reasonable usage of P. boleiriana as a model for the early evolution of Isoptera or even of the clade Cryptocercus+Isoptera. Cryptocercus thus remains an appropriate model-taxon-by-homology for early termite evolution. As compared to P. boleiriana, some other Blaberidae (such as the Panesthiinae Salganea) appear more useful as model-taxa-by-homoplasy for the early evolution of the Cryptocercus+Isoptera clade, as their brooding behavior is more elaborate than in P. boleiriana.     

Toxicity of fatty acid salts to German and American cockroaches

The toxicity of fatty acid salts to German, Blattella germanica (L.), and American cockroaches, Periplaneta americana (L.), was evaluated. Potassium and sodium laurate caused up to 95% mortality of German cockroaches and 100% mortality of American cockroaches. Even-numbered potassium fatty acid salts, C8-C18 were assessed for toxicity at 0.125, 0.25, 0.5, 1, and 2% concentrations by a 30-s immersion of cockroaches. The more soluble of the fatty acid salts at 2% concentration caused 65-95% mortality of German cockroaches and 100% mortality of American cockroaches. Potassium oleate, C18, was most toxic to both German (LC50 = 0.36%) and American (LC50 = 0.17%) cockroaches. Fatty acid salt solutions on a substrate were tested by placing cockroaches in contact with treated floor tiles immediately after application (wet) or after the solutions had dried. Sodium laurate and potassium caprate caused mortality of German (62 +/- 17.4 and 58 +/- 12.6%, respectively) and American cockroaches (52 +/- 18.5 and 28 +/- 4.9%, respectively) on wet tiles, whereas potassium oleate caused mortality of German cockroaches (67 +/- 14.1%) only. Dry fatty acids caused no mortality among exposed cockroaches. Fatty acid salt solutions can be effective in killing German and American cockroaches but only when insects are thoroughly wetted with 1-2% fatty acid salt solutions.     

Strain differences in the response of German cockroaches (Dictyoptera: Blattellidae) to emulsifiable concentrates.

The response of a susceptible and two pyrethroid-resistant field strains of the German cockroach, Blattella germanica, to four emulsifiable concentrates (ECs)--Tempo (cyfluthrin), Demon (cypermethrin), Dursban (chlorpyrifos) LO, and XRM 5184 (chlorpyrifos)--was investigated. Application rates were 0.4, 0.1, 0.5, and 0.5%, respectively. Susceptible cockroaches avoided dried formulations of the pyrethroids Tempo and Demon, but resistant cockroaches did not; avoidance was greater with Demon than with Tempo. Filter papers freshly impregnated (wet) with Demon and Tempo flushed susceptible cockroaches (Demon greater than Tempo). Resistant cockroaches were flushed only by Demon, but less so than susceptible strain cockroaches. No mortality occurred in experiments with the pyrethroids. Dried formulations of Dursban LO and XRM 5184 had little, if any, repellency to nymphs of either the susceptible or resistant strains. Initially (1-3 h), most cockroaches settled on treated papers. Subsequent movement off treated papers was a step in the process leading to knockdown. At 24 h, mortality of susceptible cockroaches was 100% in the experiment with Dursban LO and 95% in the experiment with XRM 5184. Highest mortality in a resistant strain (40%) was in the contact experiment with Dursban LO. In contact repellency and flushing experiments, mortality was higher with Dursban LO than with XRM 5184. Neither chlorpyrifos formulation flushed cockroaches effectively. Mortality in flushing experiments was less than in the contact repellency experiments.     

Evaluation of attractants for monitoring populations of the German cockroach (Dictyoptera: Blattellidae)

Lures that are used to attract German cockroaches, Blattella germanica (L.), to traps were compared in olfactometer assays in the laboratory and in trapping experiments in cockroach-infested homes and a swine farm. In olfactometer assays, AgriSense GP-2 was the most attractive lure, followed by peanut butter, and distiller's grain. Other lures, including Trapper tablet; Victor pheromone, a crude fecal extract that ostensibly contains B. germanica aggregation pheromone; and Victor food lure elicited upwind orientation from <50% of the test insects. Peanut butter and distiller's grain were equally attractive in trapping experiments in swine production barns and they captured significantly more cockroaches than the GP-2 tablet or the Victor pheromone lure; the commercial lures failed to attract significantly more cockroaches than the unbaited control traps. When tested against blank controls, cockroaches preferred to rest in shelters that contained the aggregation pheromone-based lure (Victor), but this lure was the least attractive to cockroaches in olfactometer assays. These results do not support claims that commercial crude fecal extracts attract cockroaches to traps, and they highlight a need for developing more attractive lures for detection of cockroaches and for monitoring populations.     

Complex Dynamics Based on a Quorum: Decision-Making Process by Cockroaches in a Patchy Environment

In the absence of complex communication and a global knowledge of the environment, cockroaches are able to assess the availability of resources and to reach a consensual decision: the group aggregates in a single resting site. We show that the aggregation dynamics and the collective shelter selection of cockroaches are influenced by their social context as, unlike single individuals, groups of cockroaches are more likely to respond to environmental heterogeneities. The decision of individuals to stay under a shelter relies on the modulation of their resting time, according to the perception of two local cues: (1) the shelters luminosity and (2) the number of congeners. This study on the cockroach species Periplaneta americana highlights a shelter-selection mechanism based on an amplification process resulting from the interactions between congeners. This mechanism leads to complex spatiotemporal aggregation dynamics characterized by transient bimodality, bifurcation patterns (shelter selection) and the existence of a quorum size in the settlement behaviour of the cockroaches. Finally, we discuss the generic aspect for other gregarious species of the collective decision-making process demonstrated for cockroaches.     

Use of fecal extract trails to enhance trap catch in German cockroach (Dictyoptera: Blattellidae) monitoring stations

An aqueous extract of German cockroach, Blattella germanica (L.), fecal material was evaluated for inducing trail-following behavior in German cockroaches. In arena tests the fecal extract was found to stimulate trail following in 74% of adult male cockroaches. Significantly fewer cockroaches (22%) followed water-treated (control) trails. Residual activity of the fecal extract trails was evaluated by bioassay after the trails had been stored in the refrigerator or in the open air. Although trails stored in the refrigerator showed no decline in activity after 14 d, those stored in the open air declined significantly after 3 d, inducing only 40% of adult male cockroaches to follow the trail. After 7 d the activity of trails stored in the open air was further reduced to 23%. The ability of fecal-extract trails to influence trap catch in monitoring stations was determined by bioassay. Paper trails treated with fecal extract or water were positioned between cockroach harborages and monitoring stations inside 122-cm2 arenas. The presence of the fecal extract-treated trails significantly enhanced trap catch. Mean catch in the traps with fecal extract trails was 28 cockroaches compared with a mean of 11 cockroaches in the control traps. The trap catch ratios of adults to nymphs in the treated and control treatments were not significantly different.     

Estimating nutritional status of German cockroaches,Blattella germanica (L.) (Dictyoptera: Blattellidae), in the field

Nutritional status of German cockroaches from the field (HUD apartments) was estimated using uric acid content to measure amount of protein consumed, and respiratory quotient (RQ) to measure fat and carbohydrate metabolized. Initial trials demonstrated the stability of these two indicators as nymphal cockroaches grow and with timing of meals. Nutrient consumption (and presumed availability) was estimated by comparing uric acid content and RQ of nymphal cockroaches collected from kitchens of HUD apartments with those reared in the laboratory and provided a series of meridic diets. Uric acid content was linearly related to percentage of dietary protein (y=6.2x-32.07, r(2)=0.96) and RQ was linearly related to log(10)(% fat:% carbohydrate) (y=-0.148Log(x)+0.790, r(2)=0.68). Field-collected German cockroaches contained 10.9+/-7.7 to 22.9+/-5.1 &mgr;g/mg uric acid and RQ of 0.770+/-0.024 to 0.803+/-0.260. Comparatively, cockroaches provided rodent chow had greater uric acid content (125.1+/-9.6 &mgr;g/mg) and RQ (0.878+/-0.022). Employing linear calibration and these regressions, diet consumed by German cockroaches in the field was estimated at 7+/-3% to 9+/-3% protein and equivalent amounts of carbohydrates and fat as an energy source. German cockroaches in the field consume less protein and carbohydrates, and more fat compared to those provided a standard laboratory diet such as rodent chow. Diet available in the field is considered suboptimal, resulting in physiological stress; the biological implications of this stress are discussed.     

Opioid involvement in the control of feeding in an insect, the American cockroach

Administration of the kappa opiate agonist, U-50,488H (0.10-10 mg/kg), produced over three hours a significant dose-dependent increase in the ingestive responses of free feeding American cockroaches, Periplaneta americana. These effects could be decreased by the opiate antagonist, naloxone (1.0 mg/kg), with naloxone by itself blocking the augmented feeding responses of food-deprived cockroaches. The mu opiate agonist, morphine (1.0-20 mg/kg) caused a significant dose-dependent and naloxone-reversible increase in the locomotory activity of cockroaches. These results suggest that opioid systems may be involved in the control of the feeding in cockroaches in a manner analogous to that proposed for vertebrates.     

Tracking dietary habits of cave arthropods associated with deposits of hematophagous bat guano: A study from a neotropical savanna

Carbon and nitrogen stable isotopes were used to track major dietary variations in arthropods found in a cave located in a neotropical savanna in Central Brazil. We determined the δ¹³C and δ¹⁵N for cave crickets, cockroaches, spiders, guano of a hematophagous bat, and leaf litter found on the ground near the cave entrance. The δ¹³C and δ¹⁵N for the cricket and cockroaches showed that bat guano was not the only food item for these arthropods. They had intermediate δ¹³C and δ¹⁵N between bat guano and leaf litter, which means that they consumed additional food resources other than guano in their diet, independent of distribution of guano deposits in the cave. The spiders, predators with great mobility, seemed to not have a preferential diet item since their isotope signals indicated they hunt both crickets and cockroaches. The δ¹³C of the bat guano (?15.4‰) indicated that the diet of these hematophagous bats relied on animals fed with C₄ plants. The conversion of native savanna vegetation of which the debris is mostly from C₃ plants, to pasture, based on C₄ African grass, a remarkably common land use transformation in the region, is indirectly influencing the diet of hematophagous bats, which basically relied on exotic fauna. The C and N stable isotope ratios showed that the arthropods inside the cave do not rely solely on bat guano for their diet, but interact directly with the external environment, through litter debris, indicating a significant exchange of energy and matter between the cave environment and the surrounding area.     

Susceptibility of cockroaches (Dictyoptera: Blattellidae, Blattidae) to infection by Steinernema carpocapsae.

The susceptibility of American cockroaches, Periplaneta americana (L.); smoky brown cockroaches, P. fuliginosa (Serville); oriental cockroaches, Blatta orientalis L.; German cockroaches, Blattella germanica (L.); and brownbanded cockroaches, Supella longipalpa (F.), to Steinernema carpocapsae Weiser (All strain) was evaluated under laboratory conditions. A 1-ml water suspension containing 500,000 nematodes was placed on filter paper in a petri dish or the pad of a bait station. German, brown-banded, oriental, and smoky-brown cockroaches died within 1 d after placement in the petri dishes. The relative order for the LT50s were American greater than oriental greater than smoky-brown greater than brown-banded = German. All cockroaches actively groomed nematodes from legs and antennae of forced (petri dish) exposure. The LT50s for S. carpocapsae for nonforced (bait station) exposure were significantly greater than those for forced exposure. The LT50s were 3.25, 4.13, 9.86, and 11.38 d for brown-banded, German, oriental, and smoky-brown cockroaches, respectively. The relative order of the LT50s after forced (American greater than oriental greater than smoky-brown greater than German = brown-banded) and nonforced (American greater than smoky-brown greater than oriental greater than German greater than brown-banded) exposure to S. carpocapsae was inversely related to the moisture of their preferred habitats.     

Seasonality of peridomestic cockroaches (Blattoidea: Blattidae): mobility, winter reduction, and effect of traps and baits.

Populations of smokybrown cockroaches, Periplaneta fuliginosa (Serville), and Eurycotis floridana (Walker) were studied to compare mobility and population size between fall 1985 and spring 1986 seasons at site A, and to assess the effect of a combination of traps and baits at site B in northcentral Florida. Adult smokybrown cockroaches were more mobile in the spring than in the fall; a similar trend for E. floridana adults was not significant. Overall population levels were reduced after winter by approximately 73%. No significant shift in spatial distributions of nymphs occurred, but adult distribution changed from a predominance in palms (fall) to hardwood trees with tree holes (spring), suggesting that this habitat offers better survival during winter. Removal of cockroaches by trapping at site B, followed by a single application of dry distiller's grain containing 0.5 chlorpyrifos, reduced expected population levels (based on site A data) by 90% measured at 6 mo after treatment. These data refute the hypothesis that an increase in numbers of cockroaches infesting homes in the fall is due to an increase in mobility. Instead, the results suggest that population size and proximity of principal habitats to the home are probably responsible for domestic infestations in the fall. Use of traps, baits, or both at these foci significantly reduce populations over an extended period.     

Comparison of several traps for catching German cockroaches (Dictyoptera: Blattellidae) under laboratory conditions

German cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae), catch by five types of traps and modifications of each, were tested under controlled laboratory conditions. Cockroach catch differed significantly among traps. Lo-line trap caught the greatest number of cockroaches in the test arena for each size class (23% small nymphs, 39% of gravid females, and 60% of other size classes in the experimental arena). Jar traps caught the least number of cockroaches in the test arena for each size class (range, 7-23% of each size class trapped). Modifications of traps also altered catch of cockroaches. Food bait tablets increased catch significantly; however, increases were small (<10%). Size of traps did not affect catch; whole traps or half traps caught the same number of cockroaches. Jar traps were much less effective than sticky traps, catching only half the number of cockroaches as sticky traps. A thin layer of petrolatum was a more effective barrier in jar traps to cockroach escape than powdered Olancha clay. Traps with petrolatum caught about twice as many cockroaches as traps with clay. Trapping of any of six life stages was not significantly affected by catch of any of the other stages. Rather, trap catch of each life stage was dependent on the number of that life stage available in the experimental arenas. In conclusion, of the traps tested, the Lo-line trap was the most sensitive for measuring cockroach catch, whereas the Detector trap (one third of trap) was the most economical trap (greatest sensitivity for lowest cost).     

Transfer of ingested insecticides among cockroaches: effects of active ingredient, bait formulation, and assay procedures.

Foraging cockroaches ingest insecticide baits, translocate them, and can cause mortality in untreated cockroaches that contact the foragers or ingest their excretions. Translocation of eight ingested baits by adult male Blattella germanica (L.) was examined in relation to the type of the active ingredient, formulation, and foraging area. Ingested boric acid, chlorpyrifos, fipronil, and hydramethylnon that were excreted by adults in small dishes killed 100% of first instars within 10 d and >50% of second instars within 14 d. Residues from these ingested baits were also highly effective on nymphs in larger arenas and killed 16-100% of the adults. However, when the baits and dead cockroaches were removed from the large arenas and replaced with new cockroaches, only residues of the slow-acting hydramethylnon killed most of the nymphs and adults, whereas residues of fast acting insecticides (chlorpyrifos and fipronil) killed fewer nymphs and adults. Excretions from cockroaches that ingested abamectin baits failed to cause significant mortality in cockroaches that contacted the residues. These results suggest that hydramethylnon is highly effective in these assays because cockroaches that feed on the bait have ample time to return to their shelter and defecate insecticide-laden feces. The relatively high concentration of hydramethylnon in the bait (2.15%) and its apparent stability in the digestive tract and feces probably contribute to the efficacy of hydramethylnon. To control for differences among baits in inert ingredients and the amount of active ingredient, we compared 1% chlorpyrifos with 1% hydramethylnon in identical baits. Again, hydramethylnon residues provided greater secondary kill, but the results highlighted the importance of the inert ingredients. We conclude that, in the absence of cannibalism and necrophagy, translocation of baits and secondary kill are most effective with slow acting insecticides in palatable baits that can traverse the digestive tract and be deposited within and around the cockroach aggregation.     

Detection of insecticide resistance in the German cockroach (Dictyoptera: Blattellidae) with glue-toxin traps.

Glue that contained an insecticide was evaluated for its ability to yield useful toxicological data for German cockroaches, Blattella germanica (L.). Toxicities of three classes of insecticides were evaluated by topical applications (LD50) and exposure to insecticide-impregnated glue (LC50). Cockroaches that were resistant to topical insecticide applications were also resistant to the glue formulation. Reliability was greatest when mortality was scored 40 to 48 h after the cockroaches were placed on the glue. This method should be adaptable for insecticide resistance monitoring of German cockroaches.     

中国医学昆虫研究的进展与成就

<正> 世界上一半以上的人体传染病是以医学昆虫作为媒介而传播的,加之因它们刺叮吸血等活动对人畜造成的骚扰和影响,严重威胁人类的健康,因此人们很早就对医学昆虫引起了注意。我国早在公元前100多年西汉刘安撰写的淮南子中就已提到“孑孓为蚊”。但是人类对医     

Cockroach pollination and breeding system of Uvaria elmeri (Annonaceae) in a lowland mixed-dipterocarp forest in Sarawak

Tropical forest plants are known to be pollinated by a diverse array of animals. Here we report on the pollination of a woody climber species, Uvaria elmeri (Annonaceae), by cockroaches in a lowland mixed-dipterocarp forest in Sarawak, Malaysia. To the best of our knowledge, this is the first report of pollination by cockroaches. The cauliflorous flowers in the understory are protogynous and bloomed for 50 h. An odor similar to decayed wood or a mushroom was secreted by flowers and was stronger during the male stage. Pollinators were cockroaches (Blattellidae) and drosophilid flies (Drosophilidae). Cockroaches, the main pollinators, visited flowers during both female and male stages at night, feeding on stigmatic exudate and pollen. Drosophilids, the secondary pollinators. mainly visited female-stage flowers during daytime, fed on stigmatic exudate. and laid eggs on stigmas. Neither autogamy nor self-compatibility was observed. Fruit production appeared to be pollen-limited. The fruit set, which was 2% of flowers in natural condition, was significantly lower than the 30% fruit set obtained by artificial cross-pollination. We discuss the traits of cockroaches as pollinators and the breeding system of U. elmeri.     

Communication in the courtship of a madagascan hissing cockroach. II. Effects of deantennation

The role of the antennae in courtship was studied by removing the antennae bilaterally from both male and female cockroaches, which were then paired with intact animals. These experimental pairings were compared with each other and with pairings of normal animals. Significant deviation from normal behaviour occurs in both the deantennated and the intact members of experimental pairs. When males are deantennated and paired with intact females the timing of courtship is prolonged and male cockroaches misdirect many of their copulation attempts. Under these conditions the intact female cockroaches perform some behaviours more frequently, in particular mounting and palpation. When deantennated females are paired with intact males, very little courtship ensues. The results suggest that information important to the progress of courtship is provided by both antennal inputs and antennal movements, and that the cockroaches are capable of some behavioural flexibility when deprived of this information.     

Pollination efficiency of cockroaches and other floral visitors of Clusia blattophila

• Cockroaches have rarely been documented as pollinators. In this paper we examine whether this is because they might be inefficient at pollination compared to other pollinators. Clusia blattophila, a dioecious shrub growing on isolated rocky outcrops in French Guiana, is pollinated by Amazonina platystylata cockroaches and provides a valuable system for the study of cockroach pollination efficiency.
• We examined the species composition of the visitor guild and visitation rates by means of camcorder recordings and visitor sampling. Then, we investigated the capacity for pollen transfer of principal visitors and found correlations between visitation rates and pollen loads on stigmas. In an exclusion experiment we determined the contributions of individual species to pollination success.
• Amazonina platystylata, crickets and two species of Diptera transferred pollen, but the number of transferred pollen grains was only related to visitation rates in the case of cockroaches. Crickets visited and rarely carried pollen. Dipterans were as frequent as cockroaches, carried similar pollen loads, but transferred much less pollen. An estimated 41% and 17% of ovules were pollinated by cockroaches and dipterans, respectively. The remaining ovules were not pollinated. There was no spatial variation in pollinator guild composition, but cockroaches visited flowers less frequently at the smaller study site.
• We demonstrate that cockroaches pollinate a large proportion of ovules. Their pollination service is not confined to one study site and, unlike that provided by dipterans, is not limited to certain years. We suggest that cockroach pollination has been overlooked and that cockroach‐pollinated plants, which share certain floral features, possess adaptations to pollination by cockroaches.