Inter- and intra-instar food consumption in the German cockroach, Blattella germanica

Food consumption was measured in an insecticide-susceptible (Orlando) and-resistant (Village Green) strain of German cockroach, Blattella germanica (Dictyoptera: Blattellidae), throughout each stadium. All instars exhibited a similar pattern of consumption over the course of the instar; consumption was low to moderate at the beginning of each instar, climbed steadily to a maximum near the middle, declined progressively from the mid-instar maximum, and ceased or was minimal several days before the next molt. Consumption ceased or was minimal during the final two to four days of each instar. Cumulative consumption for the six instars was significantly greater in the Village Green strain as compared with the Orlando strain. Village Green nymphs consumed 79.6±0.7 mg of rat chow while Orlando nymphs consumed 63.7±3.4 mg. Total consumption by instar increased significantly with each successive instar in the Village Green strain. In addition, Village Green sixth instar females consumed significantly more food than sixth instar males. A similar trend was observed for the Orlando strain; consumption tended to increase in each successive instar. Relative consumption rate (food consumed/cockroach/instar divided by the mean weight of the instar) was highest in the first two instars and decreased in subsequent instars.     

Influence of azadirachtin on development and reproduction of Nezara viridula L. (Het., Pentatomidae)

Abstract:  The potential of azadirachtin as an insect growth regulator was evaluated in Nezara viridula L. by applying different doses to fifth instar nymphs. At doses of 200–500 ng per insect almost all the individuals died during moulting to adults and the survivors showed a great number of nymphal characteristics, and also died very soon after. At lower doses, from 2 to 50 ng per insect, approximately 50% of the adults seemed normal. No effect was observed during the last nymphal instar, even at the highest dose applied. The fertility and fecundity of adults, males and females, developing from nymphs treated with different low doses of azadirachtin were also studied. When azadirachtin was applied at 20 ng per insect on fifth instar nymphs, females developing from these nymphs showed a conspicuous reduction of fecundity. This same effect was evident when untreated females mated with males obtained from treated nymphs. Finally, azadirachtin applied at 1  μ g/cm² to the oviposition surface showed a remarkable oviposition repellency.     

Endocrine manipulations and ontogenesis of male sexual behaviour in Locusta: studies on azadirachtin-induced over-aged nymphs

ABSTRACT. Dose-response relations of the moult-inhibitory and lethal effects of azadirachtin (AZA) injected into fifth and fourth instar hoppers of Locusta migratoria migratorioides are presented. The optimal dose for obtaining maximum number of long-surviving over-aged nymphs is 1.6 and 1.0 μg of AZA per insect for young fifth and fourth instar nymphs, respectively. Over-aged male nymphs are capable of exhibiting sexual behaviour. The mating behaviour of fifth instar over-aged male nymphs, and of chemically allatectomized but otherwise similar over-aged male nymphs (obtained by combined precocene treatment and injection of AZA), with and without injections of exogenous Juvenile Hormone III (JH), is investigated quantitatively; the results are compared with those obtained for normal, chemically allatectomized, and chemically allatectomized plus JH-injected adult males. Over-aged fifth instar male nymphs show a low intensity of mating behaviour and in chemically allatectomized ones this intensity is even lower. Injections of JH intensify the mating behaviour of chemically allatectomized fifth instar over-aged male nymphs in a dose-dependent way, but less markedly so than in chemically allatectomized adult males. We conclude that the intensity of male mating behaviour of the over-aged nymphs is subnormal and their response to the mating behaviour intensifying effect of the JH is weaker than that of adult males. The relations between endocrine factors and ethological ontogenesis of male sexual behaviour in locusts are discussed.     

Toxicity of several insecticide formulations against adult German cockroaches (Dictyoptera: Blattellidae)

Toxicity of bendiocarb, chlorpyrifos, cyfluthrin, cypermethrin, fenvalerate, hydramethylnon, malathion, propetamphos, propoxur, and pyrethrins against the adult German cockroaches, Blattella germanica (L.), was investigated. At LD50, cyfluthrin was the most toxic insecticide to adult males (0.53 microgram/g), adult females (1.2 micrograms/g), and gravid females (0.85 microgram/g). Malathion was the least toxic insecticide to adult males (464.83 micrograms/g), adult females (335.83 micrograms/g), and gravid females (275.90 micrograms/g). Males and gravid females were generally more sensitive than nongravid females to the insecticides that we tested. In tests with malathion, however, males were more tolerant. The order of toxicity of the insecticide classes varied among the stages of adult German cockroaches. The order of toxicity for males and nongravid females was pyrethroids greater than pyrethrins = organophosphates (except malathion) greater than carbamates = amidinohydrazone. The order of toxicity for gravid females was pyrethroids greater than pyrethrins = organophosphates (except malathion) greater than carbamates greater than amidinohydrazone. These differences in toxicity suggest that sex differences should be considered when determining insecticide toxicity for German cockroaches.     

Response of German cockroaches to a dispersant emitted by adult females

A bioassay technique was used to compare the response of six age/sex classes of German cockroaches, Blattella germanica (L.), to a dispersant emitted by adult females when crowded. Differences occurred among the classes in the rate, intensity, and apparently thresholds of their response. Adults, especially males, responded more strongly than nymphs. A greater repellency was associated with filter papers conditioned by non-oothecae than by oothecae bearing females, suggesting a higher emission by the former.

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Résumé Des papiers filtres contaminés ont été utilisés pour comparer les réponses de six catégories (âge/sexe) de Blattella germanica à une substance antiagrégative émise par les femelles adultes groupées. Des différences apparaissent entre les catégories quant aux taux, intensité et seuils apparents des réponses. Les adultes, particulièrement les mâles, répondent plus vigoureusement que les larves. Le pouvoir répulsif des papiers filtres contitionnés par des femelles ne portant pas d'ootheque était supérieur à celui de femelles porteuses; ceci suggère une plus forte émission par les premières.

     

Response of German cockroaches to aggregation pheromone emitted by adult females

The response of early, middle and late instar (mixed sexes), adult male, and gravid and non-gravid female German cockroaches to aggregation pheromone on filter papers conditioned by gravid and non-gravid females was studied. Cockroaches were attracted to and settled on each of the conditioned papers. Classes varied in the strength of their response to conditioned papers, relative response to gravid versus non-gravid female conditioned paper, and in clustering behavior. A significantly greater attraction of all classes except middle instars and non-gravid females to paper conditioned by non-gravid females suggests that non-gravid females emit more aggregation pheromone than gravid females. Possible explanations of differences in response with age/sex class, including an enhanced attraction of males from female sex phermone, are discussed.

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Résumé L'étude a porté sur les réponses de six groupes/âges/sexes de B. germanica à des papiers filtres imprégnés de phéromones émises par des femelles pleines ou non. Tous les groupes ont été attirés par les papiers traités, mais les attractions des stades larvaires moyens ou âgés ont été inférieures aux autres. 4 groupes sur 6 ont été plus attirés par le papier traité avec des femelles ne contenant pas d'oeufs mûrs que par les femelles pleines, ce qui suggère une plus forte émission par les femelles sans oeufs mûrs. Les stades larvaires moyens ont été les seuls à être plus attirés par le papier traité avec les femelles pleines. Les femelles ne contenant aucun oeuf ne manifestent aucune préférence. La tendance à former des amas inégaux était moins nette pour les stades larvaires moyens et âgés que pour les autres groupes. Les premiers stades ont montré une tendance très nette à se rassembler sur le même papier. Le rassemblement de mâles adultes sur du papier traité avec des femelles ne contenant pas d'oeufs peut avoir été partiellement une réponse à la phéromone sexuelle femelle qui avait imprégné le papier pendant le conditionnement.

     

Synergism between Metarhizium anisopliae (Deuteromycota: Hyphomycetes) and Boric Acid against the German Cockroach (Dictyoptera: Blattellidae)

Mortality of German cockroaches, Blattella germanica (L.), caused by Metarhizium anisopliae (Metschnikoff) Sorokin strain AC-1 alone and in combination with different formulations of boric acid, was evaluated in laboratory bioassays. Topical application of M. anisopliae alone (8.96 × 10⁹ conidia/m²) required 28 days to cause >92% cockroach mortality (LT₅₀ = 10 days). In contrast, in combination with boric acid (topically applied as a dust or in drinking water), M. anisopliae killed cockroaches significantly faster than without boric acid. M. anisopliae conidial dust (8.96 × 10⁸ conidia/m²) with either 12.5% (w/w) boric acid dust or 0.1% (w/v) boric acid in drinking water killed 100% of the cockroaches in only 8 days (LT₅₀ = 5 days) and 10 days (LT₅₀ = 6 days), respectively, without compromising the fungus emergence from cadavers. Replacement of M. anisopliae with flour dust or heat-killed M. anisopliae conidia eliminated this effect, demonstrating that it was not the consequence of greater boric acid ingestion due to more extensive cockroach grooming upon exposure to M. anisopliae conidia. Moreover, injections of a low dose of M. anisopliae, which caused only 30% mortality, together with sublethal concentrations of boric acid into the cockroach hemocoel resulted in a doubling of mortality. Statistical analysis demonstrated a synergistic interaction between these two insecticides.     

Disruption of aggregation behaviour of oriental migratory locusts (Locusta migratoria manilensis) infected with Nosema locustae

Abstract:  The effect of Nosema locustae infection on the aggregation behaviour of the oriental migratory locust, Locusta migratoria manilensis , was studied using a two-choice arena olfactometer and electroantennography (EAG). Infected locusts had low antennal sensitivity and aggregation responses to faecal extracts and to locust body volatiles. Infected fifth instar nymphs had significantly lower aggregation index than the uninfected nymphs, although with fourth instars the effect on aggregation behaviour only occurred in infected females. With regard to antennal receptor sensitivity, infected adult locusts had significantly lower EAG amplitudes in response to extracts from faeces of the adult males. The effect was most pronounced in female locusts. In contrast, there was no significant difference in the EAG responses between the fifth instar male and female nymphs. Further analysis revealed that EAG responses of fifth instar nymphs and adults infected with N. locustae to the faecal extract and volatiles from fifth instar solitary-reared nymphs were not significantly affected. In contrast, infected nymphs and adults had remarkably low EAG amplitudes for the remaining stimuli.     

Effects of diet on development of Podisus nigrispinus (Dallas) (Het., Pentatomidae), a predator of the cotton leafworm

Abstract:  The effects of diet on development of Podisus nigrispinus (Dallas) (Het., Pentatomidae) were studied at 25°C, relative humidity of 60 ± 10%, and photoperiod of 14 h light : 10 h dark. Development times of P. nigrispinus nymphs were similar when fed with third or fifth instar larvae of cotton leafworm ( Alabama argillacea Hübner) (Lep., Noctuidae) or Tenebrio molitor L. (Col., Tenebrionidae). When fed with housefly larvae ( Musca domestica L.) (Dipt., Muscidae) or artificial diet, the predator had a longer development time. Independent of diet, instar or sex, the females of P. nigrispinus showed a longer longevity than the males. The total survival of the nymphal stage, on the different diets, varied from 22.46 (fed with housefly) to 77.33% (fed with T. molitor larvae). P. nigrispinus males were heavier when fed with third or fifth instar cotton leafworm larvae than when fed with artificial diet. The weight of the females varied from 37.91 (with artificial diet) to 64.68 mg (with fifth instar cotton leafworm larvae). Independently of the diet, newly emerged females of P. nigrispinus were heavier than the males. Females of P. nigrispinus which were fed with fifth instar cotton leafworm larvae had heavier ovaries than those fed other diets.     

Influence of social situation on food consumption and growth in nymphs of the house cricket, Acheta domesticus

ABSTRACT. Grouped nymphs of Acheta domesticus L. (Orth., Gryllidae), which mature faster than isolated ones (Chauvin, 1958), consumed more food per milligram of body weight and converted it to body tissue more efficiently than did isolated nymphs, during the fifth and sixth instars. Grouped nymphs; usually had fewer instars than isolated ones. Feeding and growth rates did not decline after isolation part-way through development. Previously isolated females, paired at 25 days, matured as rapidly as females paired throughout development, but isolated males paired at 25 days matured no faster than males which remained isolated. Nymphs paired with an older cricket gained weight as fast as nymphs in same-age pairs in early instars, but their rate of weight gain declined in later instars, and their maturation was slower. However, all females, and males paired with older males, were heavier at emergence as adults than were adults from same-age pairs. When grouped with both an older cricket and one of the same age, females developed at normal rates, but males still showed some retardation.     

Female affiliative preference depends on reproductive state in the African cichlid fish, Astatotilapia burtoni

Hormones play a pivotal role in reproductive behavior and havebeen implicated in mediating mate choice decisions. Here weasked whether the differences in female reproductive state dependenton changes in hormone levels correspond to changes in femaleaffiliation with males. In the African cichlid fish, Astatotilapiaburtoni, males shift between reproductive (territorial; T) andnon-reproductive (non-territorial; NT) states depending on socialcontext while females alternate between gravid (egg bearing;G) and non-gravid (NG) reproductive states independent of socialconditions. Moreover, the brain-pituitary-gonadal axis controllingreproduction and reproductive hormones is substantially remodeledin both males and females depending on reproductive state. Tomeasure affiliative preference, gravid and non-gravid femaleswere given the choice of associating with T or NT males. Gravidfemales preferentially associated with T males, whereas non-gravidfemales showed no preference. To discover whether gravid femalesuse male size independent of dominance status as a cue for theirchoice, gravid females were given a choice between territorialmales of different sizes. Gravid females preferred the smallerof two T males, but the smaller T males were significantly moreactive. Our results show that associative change could be animportant behavioral mediator between hormonal cues and reproductivesuccess, and that females use a hierarchy of cues in decision-making,preferring to affiliate with T over NT males and, among T males,preferring more active animals.     

Effects of photoperiod,temperature and melatonin on nymphal development,polyphenism and reproduction in Halyomorpha halys (Heteroptera: Pentatomidae)

Influences of photoperiod, temperature and melatonin were examined on development and color patterns of nymphs, and sternum color and reproductive fate of adults in Halyomorpha halys (brevis). Short-day accelerated nymphal development, whereas long-day accelerated reproductive maturation. The two types of photoperiodic responses at different stages may help maintain the univoltinism of this species in the field, assuring the right timing for diapause and reproduction. The pronotum of fifth instar nymphs reared under LD 11:13 shows a brown-marbled color pattern darker, with less creamy-yellowish speckles, than that of nymphs reared under LD 16:8. Short-day-reared fifth instar nymphs, which are destined to diapause in adults, had shorter white stripes on the pronotum, smaller body size, less frequent feeding and more lipid accumulation than the long-day-reared. The longer the exposure to LD 13:11 at 20 degrees C during the nymphal stage, the greater the expression of short-day associated characteristics observed in the fifth nymphal instar and adult stage. Melatonin orally administered (500 microg/ml) to insects under LD 16:8 produced slightly reduced body size, suppressed feeding, extended nymphal period and increased accumulation of lipid compared to the untreated bugs, but did not affect the incidence of diapause in females. In males, melatonin retarded gonadal development under LD16:8. These results may suggest a possible role of melatonin for the control of seasonal polyphenism and development.     

Detection of cockroach faeces: consumption of fluorescent bait and production of UV‐light‐detectable faeces from German cockroach,Blattella germanica

Cockroaches have long been recognized as a major source of allergens in the human environment. As some allergens produced by cockroaches are accumulated within their tiny faeces and may persist unseen in the environment, development of a reliable method for monitoring cockroach faeces distribution and abundance is crucial. Our aim was to explore the rate of consumption of fluorescent bait and defecation of UV‐light‐detectable fluorescent faeces from Blattella germanica (L.) (Blattodea: Ectobiidae) as a prerequisite for the establishment of faeces monitoring in the field. Laboratory experiments revealed that (1) the fluorescent bait was accepted by cockroaches as a food source and faeces produced after its consumption were fluorescent as well; (2) there was a positive relationship between the fluorescent bait consumed and production of fluorescent faeces; (3) single and brief consumption of fluorescent bait led to continuous fluorescent faeces production, giving cockroaches enough time (ca. 27 h) to deposit fluorescent faeces in an entire area of cockroach activity as well as in shelters. The amount of fluorescent bait consumed and the amount of fluorescent faeces produced was nevertheless different among males, non‐gravid females, and gravid females. We subsequently validated the new fluorescent faeces‐based monitoring technique in a semi‐field experiment with human observers, which revealed that fluorescent faeces were reliably identified and distinguished from environmental dirt when illuminated with a UV flashlight. We further discuss the biological perspectives of our findings and recommendations for practical use.     

Sexual dimorphism of arrestment and gregariousness in the bed bug (Cimex lectularius) in response to cuticular extracts from nymphal exuviae

Releaser pheromones have direct behavioural effects to arrest, attract or disperse insects, whereas interactions within groups of social insects are often influenced by primer pheromones. The behaviour of insects displaying intermediate levels of sociality is largely unexplored in this context. In the present study, both the gregariousness and arrestment (settling near the odour source) of bed bugs Cimex lectularius L. (Hemiptera: Cimicidae) in response to conspecific exuvial extracts are described. Adult males are arrested on filter papers with extracts derived from exuviae of fifth‐instar nymphs. Adult females and nymphs display no significant evidence for such behaviour. Adults of both sexes show no preference for extracts of male versus female fifth‐instar exuviae. Arrestment of adult males does not occur on papers treated with fourth‐instar exuvial extracts. Because the insects are assayed behaviourally in groups, an index is calculated describing how far bugs are away from being located independently of one another, as a measure of gregariousness. Adult males have lower values for this index (i.e. locations are closer to independence). Adult females, nymph cohorts and mixed age groups all have higher values for this index, which tend to increase over time. Females exhibit a clear increasing dose‐dependent relationship for this index. It is concluded that the extracts of fifth‐instar nymphal exuvia arrest males on refuges that possess the odour source. However, gregariousness is induced in females, without evidence of a tendency to assemble near the odour source.     

The number of tadpoles consumed by the nymphs of the giant water bug <Emphasis Type="Italic">Kirkaldyia deyrolli</Emphasis> under laboratory conditions

Giant water bug Kirkaldyia (=Lethocerus) deyrolli (Belostomatidae: Heteroptera) nymphs consume many individuals of anuran larvae (tadpoles) before they reach adulthood. However, no quantitative data on the number of tadpoles consumed have been made available until now, despite the importance of this data for the conservation of this species. The number of tree frog, Hyla japonica (Hylidae: Anura), tadpoles consumed by nymphs of K. deyrolli was examined under laboratory conditions. The number increased according to the developmental stage of the nymphs; the fifth instar nymphs were the highest consumers. The total numbers consumed by the nymphs throughout development were 155.0 ± 12.8 (average ± SD) and 172.8 ± 9.6 for the males and the females, respectively. Thus, it might be important to maintain high densities of frogs in fields to conserve the population of K. deyrolli into the future.     

The influence of temperature, photoperiod and plant type on the predation rate of Macrolophus pygmaeus on Myzus persicae

The effect of temperature and photoperiod on the rate of predation of nymphs and adults of the predator Macrolophus pygmaeus was studied using Myzus persicae prey feeding on egg-plant and pepper plants. The experiments were conducted at three photoperiods (16L:8D, 12L:12D and 8L:16D), three temperatures (20, 25 and 30 °C), and at 65% r.h. The rate of predation increased with temperature. Predation rate was affected by photoperiod on pepper but not on egg-plant. Females and fifth instar nymphs were the most voracious stages followed by third and fourth instar nymphs and males. First and second instar nymphs consumed far fewer aphids. Predation rate was higher on leaves of pepper than egg-plant, especially at 30 °C. Variation in the efficacy of this predator is discussed.     

Selection of healthy and nuclear polyhedrosis virus infectedAnticarsia gemmatalis [Lep.: Noctuidae] as prey by nymphalNabis roseipennis [Hemiptera: Nabidae] in laboratory and on soybean

Nabis roseipennis Reuter nymphs demonstrated a preference for nuclear polyhedrosis virus (NPV) — infected over healthyAnticarsia gemmatalis Hübner larvae when offered a choice of larval prey in Petri dishes and on soybean. In Petri dishes, small (second-third instar) and large (fifth-sixth instar) nymphs attacked a significantly greater number of diseased than healthy larvae at all larval instars tested (first-fifth instars) and exposure periods (2, 5 and 24 h), except that at 2 h the number of 1^st and 3^rd instar larvae attacked by large nymphs did not differ significantly (P≤0.05). Nabis roseipennis caged with larvae on individual soybean plants in the greenhouse resulted in a generally low percentage of attack by small and large nymphs after 2 days, ranging from 5.6 to 36.7%. As in the Petri dishes, the nabids showed a significant preference for diseased larvae over healthy larvae attacked for all nabid and larval sizes on soybean, with the percentage of diseased larvae attacked ranging from 28.0 to 65.4% (P≤0.05). This preference for diseased larvae on soybean as well as in Petri dishes demonstrates that the preference was not due to the close proximity in which the host and prey were found in the Petri dishes. The preference for diseased larvae may be due to a reduction in a defensive response in late stages of disease. This material is based upon work supported in part by USDA Grant No. 83-CRCR-1-1212.     

Hot and not‐so‐hot females: reproductive state and thermal preferences of female Arizona Bark Scorpions (Centruroides sculpturatus)

For ectotherms, environmental temperatures influence numerous life history characteristics, and the body temperatures (T_b) selected by individuals can affect offspring fitness and parental survival. Reproductive trade‐offs may therefore ensue for gravid females, because temperatures conducive to embryonic development may compromise females' body condition. We tested whether reproduction influenced thermoregulation in female Arizona Bark Scorpions (Centruroides sculpturatus). We predicted that gravid females select higher T_b and thermoregulate more precisely than nonreproductive females. Gravid C. sculpturatus gain body mass throughout gestation, which exposes larger portions of their pleural membrane, possibly increasing their rates of transcuticular water loss in arid environments. Accordingly, we tested whether gravid C. sculpturatus lose water faster than nonreproductive females. We determined the preferred T_b of female scorpions in a thermal gradient and measured water loss rates using flow‐through respirometry. Gravid females preferred significantly higher T_b than nonreproductive females, suggesting that gravid C. sculpturatus alter their thermoregulatory behaviour to promote offspring fitness. However, all scorpions thermoregulated with equal precision, perhaps because arid conditions create selective pressure on all females to thermoregulate effectively. Gravid females lost water faster than nonreproductive animals, indicating that greater exposure of the pleural membrane during gestation enhances the desiccation risk of reproductive females. Our findings suggest that gravid C. sculpturatus experience a trade‐off, whereby selection of higher T_b and increased mass during gestation increase females' susceptibility to water loss, and thus their mortality risk. Elucidating the mechanisms that influence thermal preferences may reveal how reproductive trade‐offs shape the life history of ectotherms in arid environments.     

Development of an artificial diet for the western corn rootworm

Toxicants may cause insects to avoid a bait, and yet bait efficacy is dependent upon insects ingesting it in adequate quantities. Amounts ingested are, in turn, determined by meal frequency, meal durations and ingestion rate within meals, but to date no report has been made of these variables for domestic cockroaches. We report an experiment in which sixth instar German cockroach, Blattella germanica, nymphs were initially able to self-select their protein and carbohydrate intake independently, then daily at the start of the scotophase some insects had their choice of foods replaced by a single treatment food, which varied through the presence or absence of protein, carbohydrate, and insecticide. Insect behaviour was recorded for the following 5 h, and the data were subsequently subjected to bout analysis in order to identify discrete meals. The age of insects in days on first exposure to a treatment food (`age') and the amount of food eaten in the observation period were both recorded and included in the analysis. Amounts eaten were affected by insect age and food nutrient content, but not by the presence of insecticide. Toxicant effects were, however, seen on average meal duration and meal frequency, in interactions with age and food nutrient effects. These results suggest ways in which direct observations of behaviours may lead to improved bait design.     

Effects of hexane extract of Lantana camara leaves on reproductive bioactivities of Dysdercus koenigii Fabricius (Heteroptera: Pyrrhocoreidae)

Effects of hexane extract of Lantana camara leaves were investigated on reproductive bioactivities of Dysdercus koenigii by assessing mating behavior, oviposition behavior and fertility of the adults emerged from treated fifth instar nymphs. Leaves of L. camara were extracted in hexane by ‘cold extraction method’. The fifth instar nymphs were treated with the extract by ‘dry film residual method’ for 24 h and the adults emerged from these nymphs were used for the experiments. The results indicated that treated males showed altered courtship behaviour, lesser number of mounting attempts and took relatively more time to mate than the normal males. The treated females, very often, exhibited mating refusal and non-receptive behaviour towards the courting males. This led to decrease in percent successful mating. Also, the mating in the treated insects frequently got disrupted and terminated prior to insemination. The treatment of the females with the extract resulted in alteration of their oviposition behaviour. Consequently, the treated females laid lesser number of egg batches and total number of eggs in their life span. Although the eggs laid by the treated females were fertile, the percent hatchability was lesser than normal. The results signify that hexane leaf extract of L. camara possesses phytochemicals, which adversely impaired the reproductive bioactivities of D. koenigii. Therefore, some of these compounds individually or synergistically can be employed in integrated pest management of D. koenigii by hampering its reproductive potential.