We evaluated the repellent activity of 12 Apiaceae plant essential oils and their components against male and female adult German cockroaches, Blattella germanica, to find new natural repellents. Of the plant essential oils tested, ajowan (Trachyspermum ammi) and dill (Anethum graveolens) essential oils showed the most potent repellent activity against male and female adult German cockroaches. Of the compounds identified, carvacrol, thymol, and R-(-)-carvone showed >80% repellent activity against male and female adult German cockroaches at 0.2 mg/L air concentration. S-(+)-Carvone, (+)-dihydrocarvone, and terpinen-4-ol showed >70% repellent activity against male and female adult German cockroaches at 0.8 mg/L air concentration. Our results indicated that Apiaceae plant essential oils and their constituent have good potential as natural repellents against adult German cockroaches.

Cockroaches are insects of the order Blattodea, sometimes also called Blattaria, of which about 30 species out of 4,600 total are associated with human habitats. About four species are well known as pests. Among the best-known pest species are the American cockroach, Periplaneta americana, which is about 30 mm long; the German cockroach, Blattella germanica, about 15 mm long. We researched growing condition of in-vitro(temperature and humidity) for P. americana and B. germanica. The cockroach is divided in three sections; the body is flattened and broadly oval, with a shield-like pronotum covering its head. A pronotum is a plate-like structure that covers all or part of the dorsal surface of the thorax of certain insects. They also have chewing mouth parts, long, segmented antennae, and leathery fore wings with delicate hind wings. The third section of the cockroach is the abdomen. We measured size of head, abdomen, and body length during differential stages. Also, we checked number of egg, size of egg, hatching rates, period of former laying eggs, and laying periods etc.

Vitellogenins (Vgs) are precursors of the major egg storage protein, vitellin (Vn), in many oviparous animals. Insects Vgs are large molecules (200-kD) synthesized in the fat body in a process that involves substantial structural modifications (e.g., glycosylation, lipidation, phosphorylation, and proteolytic cleavage, etc.) of the nascent protein prior to its secretion and transport to the ovaries. However, the extent to which Vgs are processed in the fat body varies greatly among different insect groups. We were cloned Vgs partial genes PaVgs and BgVgs from Periplaneta americana and Blattella germanica. Real-time quantitative PCR shows that PaVgs and BgVgs were differential-regulated with aging. In insects, glutathione S-transferases (GSTs) are enzymes involved in detoxification of insecticides. We were cloned GST partial genes PaGST and BgGST from Periplaneta americana and Blattella germanica. Real-time quantitative PCR shows that PaGST and BgGST were up-regulated with aging, and the mRNA level of PaGST and BgGST was higher in 4℃ and 37℃ than room temperature. The expression level of PaGST and BgGST exposure to temperature stress suggests that PaGST and BgGST are up-regulated after exposure low and hige temperature treatments.

This study was carried out to investigate the inhabitation features of cockroaches in Jejusi, Korea. For sampling, fourteen sites were selected from every two sites of seven different habitat categories, including dwelling house, Korean restaurant, Japanese restaurant, Chinese restaurant, tea-room, hotel-inn and hospital. The cockroaches were weekly captured using sticky-traps from March, 2005 to February, 2006. Studies were focused on the temporal fluctuations of the total sample and two developmental stages (nymph and adult), the sex ratio, the positive trap percentage, and the comparative population sizes of the habitats. The positive trap percentage was 16.64%. Three species, Blatella germanica, Periplaneta americana, and Periplaneta fuliginosa, were confirmed to inhabit in Jejusi. The predominant species was P. fuliginosa (89.16%). Meanwhile, P. americana and B. germanica were shown to be much lower population size (6.44 and 4.40%, respectively). The mean sex ratio was 0.75% (males/females): B. germanica, 0.62%, P. americana, 0.29% and P. fuliginosa, 0.87%. The nymphs (82.19%) surpassed the adults (17.81%) in the individual number. Periplaneta fuliginosa also exceeded much more the other two species (P. americana and B. germanica, 5.37% and 1.67%, respectively) in the nymph number/the collected cockroaches. Both curves of the nymph and adult in the seasonal population change of P. fuliginosa made the peaks at September. This result suggested that the life cycle of this species is univoltine. The positive trap percentage and population size in the Japanese restaurant where was shown to be the most heavily polluted habitats by cockroaches were 20.67% and 0.79 (individuals/trap/week), respectively. Also, Chinese restaurant and dwelling house where were shown to be comparatively high polluted were 31.67% and 23.75% in positive trap percentage and 0.76 and 0.40 in population size, respectively. In contrast, hotel-inn, tea-room, hospital and korean restaurant were shown to be quite or very low numbers as 16.50%, 16.00%, 6.20%, and 6.00% in positive trap percentage, and 0.37, 0.18, 0.10, 0.06 in population size, respectively. It was concluded that there were differences in the species composition and the actual living conditions of the cockroach between Jejusi and other cities of Korea.

Olfactory sense is an essential modality for insects to locate hosts, mates, oviposition sites, and food resources in nature. Based on many studies so far, insect olfactory systems in periphery as well as central nervous systems seem to be highly plastic with behavioral and physiological changes associated with learning and memory, sensory processes, and other developmental processes. Eventually, it is also evident that these plasticity and processes in olfactory systems are modulated by a various ensemble or sets of neuropeptides. The olfactory reception in the peripheral systems of the cockroach, Periplaneta americana, associated with learning behaviors, is fluctuated by the circadian rhythm, which is subsequently thought to control the titer of hormones and various neuropeptides concomitantly. However, it remains still elusive how neuropeptides and neuroendocrine systems modulate olfactory system in the peripheral systems in cockroaches as well as any other insects. Here, our aims to characterize the ultrastructure of these neuro-endocrine systems in the peripheral olfactory systems in American cockroach, Periplaneta americana. Using in situ hybridization methods, we found out that tachykinin and its receptors seem to be important neurotransmission machineries in the periphery to convey the arousal signals from the insect brain. Our findings also indicate complicated endocrine systems connected with central nervous systems may modulate the olfactory reception in the periphery.

A study has been performed on the cockroach knowledge and perception of managers, employees and consumers, and the cockroach control management in food service institutions. A total of 759 subjects including 101 managers, 293 employees and 365 consumers was surveyed in Seoul and Pusan areas from July 1994 to September 1994. The results obtained are as follows: The mean rates of the cockroach knowledge (i.e. 62.26/100.0) and perception (i.e. 23.67/30.0) of the consumers were significantly (p<0.001) lower than those of the managers (i.e. 68.87/100.0 and 25.30/30.0, respectively) and the employees (i.e. 69.09/100.0 and 26.99/30.0, respectively). In the cockroach detection rates, however, much higher rate was seen in the consumer group (i.e. 79.5%) than the manager (i.e. 43.3%) and the employee (i.e. 48.5%) groups. Forty and seventy percents of the subjects have suffered from allergies and nuisance by cockroaches, respectively. The cockroach control was performed by 75.5% of the food service institutions and 70.8% of them contracted with pest control operators to reduce the cockroach populations. The cockroach control methods of the operators were aerosol (40.7%) and insecticidal baits (30.5%). Only 33.7% of the institutions had the budgets for the cockroach control. For public health, the managers and the employees of the institutions need to be educated about cockroaches and hygiene. Also, it is suggested that cockroaches be regularly controlled by professional pest control operators.