The corpora allata (CA) of both intact and ovariectomized Blattella germanica adult females exhibited a high degree of bilateral symmetry in the rate of juveni le hormone (JH) biosynthesis, the mean size of CA cells, and gland volume (81.3%, 98.3%,and 100% respectively wi th less than a twofold difference between the two glands in CA pairs). This permitted us to split each CA pair randomly, mea...

Seven commercial essential oils extracted from the plant species Boesenbergia rotunda (L.) Mansf., Citrus hystrix DC., Curcuma longa L., Litsea cubeba (Lour.) Pers., Piper nigrum L., Psidium guajava L. and Zingiber officinale Roscoe, and naphthalene as a control, were evaluated for repellent activity against the three cockroach species Periplaneta americana (L.), Blattella germanica (L.) and Ne...

BACKGROUND INFORMATION Epidermal growth factor receptor (EGFR) signalling is crucial for the regulation of multiple developmental processes. Its function in relation to insect oogenesis has been thoroughly studied in the fly Drosophila melanogaster, which possesses ovaries of the highly modified meroistic type. Conversely, studies in other insect species with different ovary types are scarce. W...

Communication and learning from each other are part of the success of animal societies. Social insects invest considerable effort into signalling to their nestmates the locations of the most profitable resources in their environment. Growing evidence also indicates that insects glean such information through cues inadvertently provided by their conspecifics. Here, we investigate social informat...

This study aims to investigate changes in resistance insecticides over a ten-year period five strains of German cockroaches, Blattella germanica (Linnaeus), which had previously shown deltamethrin, propoxur, and fipronil 2012. The were reared laboratory without exposure for ten years. In 2022, they tested the same using topical application method. ratio (RR50) was calculated each strain determi...

The corpus allatum (CA) cells of adult Blattella germanica females undergo cyclic volumetric changes in relation to juvenile hormone (JH) synthesis. In intact females the size of CA cells changes synchronously during the gonotrophic cycle, resulting in cyclic JH synthesis. In ovariectomized females volumetric changes among CA cells become asynchronous, resulting in highly variable but high rate...

Twelve strains of German cockroach, Blattella germanica (Linnaeus) were collected from various locations in Peninsular Malaysia and tested for their susceptibility to three groups of insecticides applied topically. The levels of resistance were low to high (2.8 to 92×) for carbamates (propoxur and bendiocarb), low (2.0 to 7.6×) for organophosphate (chlorpyrifos) and low to moderate (1.0 to 23×)...

It has been nearly three decades since the identification of the Drosophila Sodium Channel 1 (DSC1) gene from Drosophila melanogaster. The orthologs of the DSC1 gene have now been identified in other insect species including BSC1 from Blattella germanica. Functional analyses of DSC1/BSC1 channels in Xenopus oocytes reveal that DSC1 and BSC1 encode voltage-gated cation channels that are more per...

As one of the most common sources of indoor aeroallergens worldwide, cockroach is important in causing rhinitis and asthma while the mechanisms underlying remain obscure. Since T helper (Th) type 2 polarization plays an important role in the pathogenesis of allergic diseases, we investigated the effect of Bla g 7, a pan-allergen from Blattella germanica (B. germanica), on Th polarization which ...

Tactile stimuli provide animals with important information about the environment, including physical features such as obstacles, and biologically relevant cues related to food, mates, hosts and predators. The antennae, the principal sensory organs of insects, house an array of sensory receptors for olfaction, gustation, audition, nociception, balance, stability, graviception, static electric fi...