Male German Cockroaches Research Articles

Эффективность приманки на основе денсовируса PfDNV в отношении синантропных тараканов

We present our own data on the effectiveness of insecticidal bait based on the densovirus of the smoky-brown cockroach Periplaneta fuliginosa (PfDNV) for German, American and Oriental cockroaches. On average, the mortality rate of German cockroaches was 70?% within 5 days of the experiment, which corresponds to the required indicator of bait effectiveness. The total mortality of males and females of Oriental and American cockroaches was below 70?%, which does not allow us to recommend this product for use against these species of cockroaches. It has been established that male German cockroaches are more susceptible to bait than females. A comparison of the mortality rates of German cockroaches in the absence of alternative food showed that the MAG and KR strains resistant to traditional insecticides do not differ from that of the susceptible S-NIID strain. Females of the DM strain died off 3 times longer than susceptible S-NIID females. In the presence of alternative food, a slowdown in the action of the bait was observed in females of the KR strain by 2.5 times and in DM by 4 times. Viruses are highly specific to their hosts and can lead to a significant reduction in the number of hosts. Bioinsecticides may be a necessary alternative in the control of resistant German cockroaches. Keywords: densovirus PfDNV, synanthropic cockroaches, resistance.

Evaluation of Repellency and Lethal Effects of Ultrasonic Waves on the Blattella germanica (Blattodea: Blattellidae).

The German cockroach, Blattella germanica (Insecta: Blattodea, Blattellidae), which occurs widely in human buildings, is a small cockroach species. Cockroach control chemical pesticides are toxic to the environment, and it is sometimes impossible to prevent them. Controlling Blattella germanica through ultrasonic waves can be efficient and less dangerous for the environment. In this study, the repellency and lethal effect of ultrasonic waves on male and female German cockroaches was tested in a twin glass cubic chamber at laboratory condition. The wave frequencies tested ranged from 20 to 100kHz with 5kHz steps. A signal generator generated these frequencies, and the piezoelectric transmitter of these ultrasonic waves was positioned in the chamber's center on the upper side. Fisher's test showed that there was the greatest repellency effect in both male and female at frequencies of 35 and 40kHz. According to the results of the regression test, the most lethal effect is at the frequencies of 40 and 75kHz. The operating ultrasonic frequencies investigated in this study can be used to repel and kill German cockroaches as pests endangering human health and environment.

The effectiveness of commercial gel baits against German cockroach Blattella germanica (Linnaeus, 1767) in Indonesia

Gel baits product sold commercially to the public has long been used to control German cockroach populations in urban areas. The effectiveness and resistance level of gel bait products need to be known for the successful control of German cockroaches in the field. However, there have been no reports of resistance in Indonesia. This study used toxicity tests of six gel bait products (MF, CBG, SPB, OTG, BTX, and UBA) against two populations of adult male German cockroaches (VCRU-WHO and RKMN-BKT). Fipronil, boric acid and emamectin benzoate containing gel baits were effective to knock down and kill the German cockroaches. In contrast, gel bait with imidacloprid as an active ingredient was only useful to knock down the German cockroaches. Commercial gel bait product in Indonesia are still useful in controlling German cockroaches’ populations with a time of effectiveness to cause mortality between three to four weeks after being exposed in the field and the level of cockroach resistance to gel bait are susceptible until low resistance.

Effects of Nicotine and Tobacco-Related Products on the Feeding Behavior of the German Cockroach (Blattodea: Blattellidae).

Animals use olfaction to detect developmentally significant volatile organic compounds (VOCs) in their local environment. As part of a wider study aiming to demonstrate that the olfactory responses of animals to VOCs can be modified through the creation of a drug-addicted status and association with a selected VOC, we investigated nicotine and tobacco smoke particulate (TSP) extract as possible addictive compounds for male German cockroaches, Blattella germanica (Linnaeus). In feeding experiments using an artificial food stimulus, food treated with TSP extract was preferred over untreated food. Surprisingly, nicotine, which was expected to be the most important addictive tobacco component, did not induce noticeable effects on cockroach behavior. Both TSP extract and nicotine were shown to be phagostimulants. Olfactometry assays that measured odor-mediated insect behavior demonstrated that male B. germanica did not choose TSP-extract-treated food even when attempts were made specifically to train them via this modality. These results support a hypothesis that B. germanica needs to consume TSP-containing food to show a clear preference for this stimulus and that gustatory mechanisms are involved due to compounds present in the TSP extract.

Behavioral and Morphological Studies of the Membranous Tergal Structure of Male Blattella germanica (Blattodea: Ectobiidae) During Courtship.

The male German cockroach Blattella germanica (L.) exhibits a characteristic courtship display by raising its wings, turning around, and exposing its tergal glands on the seventh and eighth tergites to the female. The male secretes a courtship pheromone from the tergal glands which induces a strong feeding response in the female, facilitating copulation. Upon multiple, detailed microscopic observations of the courtship display, we found that the male markedly expanded the intersegmental area between the sixth and seventh tergites, but deflated this area as soon as it perceived a tactile stimulus on its back by the female, while continuing to raise its wings and exposing the tergal glands. The intersegmental area is composed of two parts: a membranous posterior part of the sixth tergite, and the regular intertergal membrane. The membranous posterior part was found to be crescentic in shape and clearly separated from the intertergal membrane by traverse tongue-shaped plates. Scanning electron microscopic observation revealed that there were many orifices or pores in the membranous crescentic zone, and its morphological structure was clearly different from that of the intertergal membrane. Our observations suggest that the crescentic zone is likely a secretory gland that may play an important role at the beginning of the male courtship display, different from the tergal glands.

Antennal grooming facilitates courtship performance in a group-living insect, the German cockroach Blattella germanica

The antennae of adult male German cockroaches detect a contact sex pheromone embedded in the female’s cuticular lipids. The female pheromone stimulates courtship behavior in males, notably a wing-raising (WR) display. Within aggregations, however, cuticular lipids are disseminated by contact among group members, including nymphs and adults of both sexes, and “contamination” of cockroaches with the cuticular lipids of another stage or sex may interfere with sex discrimination and disrupt courtship. We used behavioral observations, bioassays and chemical analysis to determine how males maintain their sensitivity to sex pheromone in aggregations. Males contaminated with female pheromone displayed lower courtship, because residual female pheromone on their antennae adapted their peripheral sensilla and habituated the central nervous system. Female pheromone that contaminated the male’s antennae also elicited courtship from other non-contaminated males, disrupting their sex discrimination in the group. However, antennal grooming effectively removed female pheromone from males’ antennae and maintained their chemosensory acuity and sexual discrimination among group members. Thus, grooming of the antennae and other sensory appendages is an important strategy to enhance sensory acuity, especially in group-living insects like the German cockroach.

Repellent Activity of Apiaceae Plant Essential Oils and their Constituents Against Adult German Cockroaches

We evaluated the repellent activity of 12 Apiaceae plant essential oils and their components against male and female adult German cockroaches, Blattella germanica L., to find new natural repellents. Of all the plant essential oils tested, ajowan (Trachyspermum ammi Sprague) and dill (Anethum graveolens L.) essential oils showed the most potent repellent activity against male and female adult German cockroaches. Repellent activities of chemicals already identified in active oils were also investigated. Of the compounds identified, carvacrol, thymol, and R-(-)-carvone showed >80% repellent activity against male and female adult German cockroaches at 2.5 µg/cm2. S-(+)-Carvone, (+)-dihydrocarvone, and terpinen-4-ol showed >70% repellent activity against male and female adult German cockroaches at 10 µg/cm2. Our results indicated that Apiaceae plant essential oils and their constituents have good potential as natural repellents against adult German cockroaches.

Gustatory adaptation affects sexual maturation in male German cockroaches, Blattella germanica

AbstractAdaptations to hazardous environmental factors are essential for survival, although they may be maladaptive in conditions where the hazard is absent. In German cockroach (Blattella germanica L.) populations, glucose aversion has evolved rapidly in response to glucose‐containing insecticidal baits, but little is known about the consequences of this behaviour in the absence of bait. In the present study, glucose‐averse (GA) and wild‐type (WT) male German cockroaches are restricted to a range of nutritionally defined diets containing either glucose or fructose as the sole carbohydrate source, and time to first expression of courtship is measured by stimulating the male antennae daily with isolated antennae from receptive, 6‐day‐old females. Glucose‐averse males that are restricted to glucose‐containing diets mature their courtship responses significantly later than GA males restricted to fructose‐containing diets, whereas there is no difference in maturation of courtship responses between GA males restricted to fructose‐containing diets and WT males restricted to diets containing either sugar type. Glucose‐averse males furthermore respond later to GA female antennae than to WT female antennae, all from 6‐day‐old females. This suggests that GA females are less sexually stimulating, and the results are also consistent with earlier findings showing that GA females contain less developed oocytes than WT females at this age. These findings demonstrate that an adaptive gustatory mutation conferring protection from a toxin may have comparatively detrimental effects under conditions where the toxin has vanished, both by delaying female sexual maturation and signalling and by delaying male sexual maturation and courtship under conditions where glucose is a major energy source.

Insecticidal and acetylcholine esterase inhibition activity of Asteraceae plant essential oils and their constituents against adults of the German cockroach (Blattella germanica).

The fumigant and contact toxicities of 16 Asteraceae plant essential oils and their constituents against adult male and female Blattella germanica were examined. In a fumigant toxicity test, tarragon oil exhibited 100% and 90% fumigant toxicity against adult male German cockroaches at 5 and 2.5 mg/filter paper, respectively. Fumigant toxicities of Artemisia arborescens and santolina oils against adult male German cockroaches were 100% at 20 mg/filter paper, but were reduced to 60% and 22.5% at 10 mg/filter paper, respectively. In contact toxicity tests, tarragon and santolina oils showed potent insecticidal activity against adult male German cockroaches. Components of active oils were analyzed using gas chromatography, gas chromatography-mass spectrometry, or nuclear magnetic resonance spectrometer. Among the identified compounds from active essential oils, estragole demonstrated potent fumigant and contact toxicity against adult German cockroaches. β-Phellandrene exhibited inhibition of male and female German cockroach acetylcholinesterase activity with IC50 values of 0.30 and 0.28 mg/mL, respectively.

Evaluation of Contact Toxicity and Repellency of the Essential Oil of Pogostemon cablin Leaves and Its Constituents Against Blattella germanica (Blattodae: Blattelidae).

The aim of this research was to evaluate contact toxicity and repellency of the essential oil of Pogostemon cablin (Blanco) Bentham leaves against German cockroaches (Blattella germanica) (L.) and to isolate any active constituents. Essential oil of P. cablin leaves was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Twenty-three components were identified in the essential oil, and the main constituents were patchoulol (41.31%), pogostone (18.06%), α-bulnesene (6.56%), caryophyllene (5.96%), and seychellene (4.32%). Bioactivity-directed chromatographic separation of the essential oil led to the isolation of pogostone, patchoulol, and caryophyllene as active compounds. The essential oil of P. cablin leaves exhibited acute toxicity against male B. germanica adults with an LC50 value of 23.45 μg per adult. The constituent compound, pogostone (LC50 = 8.51 μg per adult) showed stronger acute toxicity than patchoulol (LC50 = 207.62 μg per adult) and caryophyllene (LC50 = 339.90 μg per adult) against the male German cockroaches. The essential oil of P. cablin leaves and the three isolated constituents exhibited strong repellent activity against German cockroaches at a concentration of 5 ppm. The results indicated that the essential oil of P. cablin leaves and its major constituents have good potential as a source for natural insecticides and repellents.

Study on vertical movement of the adult German cockroach, Blattella germanica, to upper floors

The vertical movement of the German cockroach Blattella germanica (Linnaeus) to upper floors was studied using a 700 cm vinyl tube as a model of a drainpipe in buildings and houses. The whole experiment was conducted in the dark. After three days of acclimatization with twenty cockroaches, the acclimated container was connected to the bottom of the tube on the third floor of a building, and two new containers were connected to the tube on the fourth floor (350 cm distant from the third floor) and fifth floors (700 cm distant), respectively. The cockroaches in each container were counted daily for four weeks. Food and water were set in the container on the third floor from the first to seventh day of the experiment, and from the eighth to 28th day, they were placed only in the containers on the fourth and fifth floors. Twenty-eight percent of both male and female German cockroaches stayed in the acclimated container for the first seven days. After food and water were moved to the new containers, many cockroaches moved to the new containers. For the last seven days, 30% of the males and 13% of the females stayed in the new containers, while 7.7% of males and 5.4% females stayed in the acclimated container. Thus, the cockroaches used the vinyl tube for both a passage and for a harborage.

Fumigant and contact toxicity of Myrtaceae plant essential oils and blends of their constituents against adults of German cockroach (Blattella germanica) and their acetylcholinesterase inhibitory activity

Fumigant and contact toxicities of 11 Myrtaceae plant essential oils and their constituents against adult male and female Blattella germanica were evaluated. Of 11 Myrtaceae plant essential oils, Eucalyptus polybractea, Eucalyptussmithii, Eucalyptusradiata, Eucalyptusdives, Eucalyptusglobulus, and Melaleuca uncinata, showed 100% fumigant toxicity against adult male German cockroaches at a concentration of 7.5mg/liter air concentration. In contact toxicity tests, E. polybractea, E. smithii, E. radiata, E. dives, E. globulus, Melaleucadissitiflora, and M. uncinata produced strong insecticidal activity against adult male and female German cockroaches. Of the essential oil constituents, terpinolene, α-terpinene, and terpinen-4-ol demonstrated strong fumigant toxicity against adult male and female B. germanica. Eugenol, isoeugenol, methyl eugenol, and terpinen-4-ol showed strong contact toxicity against adult male B. germanica. The toxicity of the constituent blends identified from M. dissitiflora essential oils indicated that terpinen-4-ol were major contributor to the fumigant activity or contact toxicity of the artificial blend. Only isoeugenol exhibited inhibition activity against male acetylcholinesterase. IC50 values of isoeugenol were 0.22mg/mL against male acetylcholinesterase.

Social interaction facilitates reproduction in male German cockroaches, Blattella germanica

Sociality can be beneficial for individuals because it may increase access to resources, provide greater protection from predators and create opportunities for mating. In some species, social conditions and experience also influence the physiology and behavioural responses of individuals. Although social facilitation of sexual maturation is poorly understood in insects, the German cockroach has served as an important model system for this phenomenon as group-housed females mature faster than solitary females. However, social modulation of male reproduction has not been investigated in this or any other nonpolyphenic insect species. We investigated the relative effects of social interactions and isolation on endocrine, reproductive and behavioural events during sexual maturation of B. germanica males. Results show that social interactions significantly facilitate juvenile hormone biosynthesis as well as protein production by the accessory reproductive glands, whereas isolation suppresses these processes. Other processes, such as accumulation of cuticular hydrocarbons, maturation of the male's courtship readiness and his readiness to copulate, appear to be relatively independent of social experience. However, both courtship and copulation latencies declined with age more in socially paired males than in isolated males. Our study is the first to reveal that social interactions have a profound effect on certain aspects of male reproductive physiology and behaviour in an insect species that does not exhibit phase or developmental polyphenism . • Social interactions affect male cockroach reproductive physiology and behaviour. • Group living facilitates juvenile hormone biosynthesis in adult males. • Group living facilitates protein production in adult male accessory reproductive glands. • Social conditions influence male sexual maturation. • Some events during sexual maturation are independent of male social experience.

Insecticidal and Acetylcholine Esterase Inhibition Activity of Apiaceae Plant Essential Oils and Their Constituents against Adults of German Cockroach (Blattella germanica)

We evaluated the insecticidal and acetylcholine esterase (AChE) inhibition activity of 11 Apiaceae plant essential oils and their constituents in adult male and female Blattella germanica. Of the 11 Apiaceae plant essential oils tested, dill (Anethum graveolens), carvi (Carum carvi), and cumin (Cuminum cyminum) demonstrated >90% fumigant toxicity against adult male German cockroaches at a concentration of 5 mg/filter paper. In a contact toxicity test, dill (Anethum graveolens), carvi (Carum carvi), cumin (Cuminum cyminum), and ajowan (Trachyspermum ammi) produced strong insecticidal activity against adult male and female German cockroaches. Among the test compounds, (S)-(+)-carvone, 1,8-cineole, trans-dihydrocarvone, cuminaldehyde, trans-anethole, p-cymene, and γ-terpinene demonstrated strong fumigant toxicity against adult male and female B. germanica. In a contact toxicity test, carveol, cuminaldehyde, (S)-(+)-carvone, trans-anethole, thymol, and p-cymene showed strong contact toxicity against adult male and female B. germanica. IC(50) values of α-pinene, carvacrol, and dihydrocarvone against female AChE were 0.28, 0.17, and 0.78 mg/mL, respectively. The toxicity of the blends of constituents identified in 4 active oils indicated that carvone, cuminaldehyde, and thymol were major contributors to the fumigant activity or contact toxicity of the artificial blend.

Different behavioral response between male and female German cockroach, Blattella germanica, to various arrangements of food and water in an experimental arena

Different behavioral response between male and female German cockroach, Blattella germanica, to various arrangements of food and water in an experimental arena

Spinosad Affects Chemical Communication in the German Cockroach, Blatella germanica (L).

Spinosad is a biopesticide, derived from fermentation by the soil-dwelling actinomycete, Saccharopolyspora spinosa, which is used to control a variety of insects. Spinosad kills a wide range of insect pests when ingested or topically applied, by overexciting the nervous system, yet is harmless to mammals and many predatory insects. Other modes of action of this insecticide have not been documented. Here, we report that a non-lethal dose of spinosad causes adult male and female German cockroach, Blattella germanica, to exhibit altered responses to their aggregation pheromone as well as to have a changed cuticular hydrocarbon profile.

Jail baits: how and why nymphs mimic adult females of the German cockroach, Blattella germanica

The male German cockroach performs a characteristic courtship behaviour upon contacting a sexually receptive female: he turns away from the female and raises his wings, thereby exposing tergal glands whose reservoirs contain phagostimulatory substances. The female then mounts the male and feeds upon these nuptial secretions; this behaviour places her in the appropriate precopulatory position. The contact sex pheromone on the cuticular surface of the female, responsible for eliciting courtship behaviour in males, consists of a blend of six components that share a common biosynthetic pathway. An excised female antenna can elicit the full courtship display in males. We found that antennae taken from either male or female nymphs of various ages also could elicit the full courtship response in adult males. We extracted lipids from the cuticular surface of nymphs and, guided by behavioural assays, we fractionated the extracts using various chromatography procedures, including flash (column) chromatography, high-performance liquid chromatography and gas chromatography. Mass spectrometry analysis of behaviourally active fractions revealed two classes of courtship-eliciting compounds: all nymphs possessed a novel, still unidentified compound that elicited courtship in adult males. In addition, in last-instar females, we isolated four of the six adult female-specific contact sex pheromone components, consistent with differentiation of the sexes at this stage, and the onset of sexual maturation of the pheromone biosynthetic machinery. Our results support the interpretation that nymphs engage in sexual mimicry to gain access to male-produced nuptial tergal secretions that are exposed and can be secured only during courtship.

New Contact Sex Pheromone Components of the German Cockroach, Blattella germanica, Predicted from the Proposed Biosynthetic Pathway

Upon contacting the cuticle of a sexually mature female, a male German cockroach exhibits a characteristic courtship behavior: he turns away from the female and raises his wings, thereby exposing tergal glands. The glandular secretion stimulates the female to mount the male and feed, thus positioning her appropriately for copulation. A multi-component contact sex pheromone produced by females is responsible for eliciting courtship behavior. The most abundant pheromone components are 3,11-dimethylnonacosan-2-one and 3,11-dimethylheptacosan-2-one, oxidation products of the abundant hydrocarbon analogs 3,11-dimethylnonacosane and 3,11-dimethylheptacosane, respectively. The C(29)-dimethyl ketone is thought to be further metabolized to two less abundant pheromone components, 29-hydroxy-3,11-dimethylnonacosan-2-one and 29-oxo-3,11-dimethylnonacosan-2-one. Based on this proposed biosynthetic pathway of pheromone production, we hypothesized that 3,11-dimethylheptacosan-2-one also would be oxidized to give two candidate pheromone components, 27-hydroxy-3,11-dimethylheptacosan-2-one, and 27-oxo-3,11-dimethylheptacosan-2-one. By using bioassay-guided fractionation and chemical analyses of cuticular extracts of virgin females and synthesis of the (3S,11S)-isomer of each of the two predicted pheromone components, we showed that the epicuticle of the German cockroach does indeed contain these two compounds. The contact sex pheromone of the female German cockroach, thus may consist of at least six biosynthetically related components.

Identification of cuticular lipids eliciting interspecific courtship in the German cockroach, Blattella germanica

The cuticular surface of sexually mature females of the German cockroach contains a sex pheromone that, upon contact with the male's antennae, elicits a characteristic species-specific courtship behavior. This female-specific pheromone is a blend of several long-chain methyl ketones, alcohols and aldehydes, all derived from prominent cuticular hydrocarbons found in all life stages of this cockroach. We found that contact with the antennae of 5 out of 20 assayed cockroach species elicited courtship behavior in German cockroach males. The heterospecific courtship-eliciting compounds were isolated by behaviorally guided fractionation of the active crude extracts and compared to the native sex pheromone components. We identified two active compounds from the cuticular extract of the Oriental cockroach, Blatta orientalis -- 11-methylheptacosan-2-one and 27-oxo-11-methylheptacosan-2-one; the former compound was confirmed by synthesis and proved to independently stimulate courtship in German cockroach males. These compounds share common features with, but are distinct from, any of the known contact sex pheromone components. This suggests that sex pheromone reception in the male German cockroach is unusually promiscuous, accepting a wide range of compounds that share certain features with its native pheromone, thus resulting in a broad spectrum of behavioral response to other species. We propose that several characteristics of their mating system -- chiefly, absence of closely related species in the anthropogenic environment, resulting in relaxation of selection on sexual communication, and a highly male-biased operational sex ratio -- have driven males to respond with extremely low thresholds to a wide spectrum of related compounds.

Responses of mosquitoes and German cockroaches to ultrasound emitted from a random ultrasonic generating device

AbstractThe repellency of ultrasound to females of two species of mosquitoes, Anopheles quadrimaculatus Say and Anopheles gambiae Giles (Diptera: Culicidae), and male and female German cockroaches, Blattella germanica (L.) (Blattodea: Blattellidae), was evaluated under laboratory conditions using a random ultrasonic device developed at Kansas State University. This device produces ultrasound in the 20–100 kHz frequency range and random sound patterns at any frequency range. Under the particular settings described in the paper, this ultrasonic device produced sound pressure levels from 91 to 101, 91 to 102, and 90 to 100 dB at the top, bottom, and side panels of the test chamber, respectively (0 dB = 20 micropascals). Sound pressure levels recorded at the center of the top, bottom, and side panels were higher than those recorded at the panel edges. Ultrasound from the random ultrasonic device failed to repel mosquitoes and German cockroaches at the different frequency ranges evaluated. Our results confirm previous findings with commercial devices producing constant sound patterns that ultrasound in general is not a promising tool for repelling mosquitoes and cockroaches.