Smokybrown cockroach

P. fuliginosa can reproduce through sexual reproduction and in some cases through parthenogenesis, which is a form of asexual reproduction.[5] In cases where females do not have access to mates, females reproduce by parthenogenesis, however, this form of reproduction is not as commonly seen as sexual reproduction.[5] Females can oviposit an average of 10 or more oothecae in favorable environments, but this is highly dependent on the cockroaches' body fat, thereby as her body mass decreases fewer ootheca are oviposited in a season.[6] The oothecae, dark brown color, commonly ranges from 11–14 millimetres (0.43–0.55 in) in length.[1] On average female cockroaches without mates live longer, than females with a mate.[5] In a study done, it was found that on average adult females lived 117–174 days, whereas females without a mate lived to 131–236 days after reaching adulthood.[5] The higher energy costs associated with oogenesis and the prevalence of oviposition point to a shorter lifespan.[5] Furthermore, an extended oviposition period occurs, as a result, fewer eggs are formed.[5] Sexual reproduction also leads to lower instances of oothecae defects without the presence of eggs compared to reproducing asexually.[5]

Females release volatile sex pheromones stimulating the mating behavior of P. fuliginosa males, which receive the chemical signals through sensory receptors located on their antennae.[7] These pheromones are made up of synthetic Periplanone-D, which is a major sex excitatory component of the pheromone chemical composition.[7] In addition, the males often participate in perching, whereby their body conformation includes a pointing downward of the head, forelegs extended, as their antennae become aligned 45° from their vertical position.[8] Whereby, in female mate calling the cockroaches' body is up high, the dorsal end of the abdomen bend towards the ground, and wings are held at a 45° angle.[8] These male cockroaches allocate significantly more time and energy to mating behaviors than females as the production of female pheromones is costly.[8] Moreover, spending 20% of their time perching, whereby in retrospect females only spend 8% of their time mate calling.[8]

Temperature and levels of humidity are factors that greatly influence the smoky brown cockroaches' cuticular water loss, therefore these insects are attracted to highly humid areas to reduce the permeability of their cuticle.[9][10] The amount of lipid composition of the cockroach also directly correlates to lower body transpiration, in addition, but provides these species with a more water barrier easing the permeability of the cuticle.[9] Therefore, as the water levels drop from sun exposure, the circulation of materials in the blood is also slowly diminishing.[9][10] Over time even when restricted to certain habitats due to the physiology of their cuticle, they are able to acclimatize through homeostasis seen by decreased salivary gland production.[10] P. fuliginosa, are able to upkeep homeostasis in fluctuating moisture regions by changing their drinking habits, and the water flow rate of fecal matter, as well as cuticle transpiration.[10] The cuticle is made up of many layers where much secretion is stored between the various plates.[11] These thick layers have various glandular cells, along with pores that connect through the cuticle to secrete the sticky protein substance.[11] The secretions of the hypodermal layer play a role in the nymph male defenses towards adult cockroaches.[11]

P. fuliginosa are considered pests in many geographical areas around the world, including the Southern United States and Japan, as they are very effective at invading urban homes, restaurants, hospitals, and many other crowded places.[2] [1] With their rapid invasion into homes, they are known as sanitary pests and have adapted to toxic bait traps being ineffective at eradicating these species.[12]

These species can be detrimental to human health, thereby due to their proximity of inhabitance to humans they are a vector for diseases from the parasitism of nematodes.[12] They are harmful due to humans through their ability to feed on fecal matter, which transmits parasites and many diseases.[1] The parasitic nematode, Leidynema appendiculata, is known to parasitize the smoky brown cockroach, in which they invade and live in the cockroach's gut.[12] The eggs of the nematode are passed through the cockroach's feces and spread to other hosts by cockroaches eating the excrement.[12] The invasion of homes by these cockroaches greatly increases the prevalence of asthma, pathogen exposure, and allergens seen.[13] Exposure to the cockroach's feces, the shed outer layer of the exoskeleton, and other body parts mainly cause the transfer of parasites and allergens.[1] In addition, human exposure to these parasitic nematodes can cause conditions such as colitis, and infections of the female reproductive tract.[14]

One of the control measures to avoid these inhabitants is the use of insecticides, thereby spraying around the exterior of the house with a 3-metre (9.8 ft)-wide barrier.[1] In addition, it has also been suggested to use these insecticides every month in the cracks, around windows, and any other accessible entry points for these, cockroaches to enter.[1] New insights have been set in using virus technology to control the smoky brown cockroach.[13] The use of the densovirus is an interesting technology to use as many methods are ill-equipped to minimize the impacts of the smoky brown cockroach as they can change their sensory behavior to insecticides over time.[12][13] In a study done, when P. fuliginosa are exposed to the artificially extracted densovirus from a diseased cockroach, high mortality occurred with exposure to low doses.[13] The use of a biocontrol agent rather than insecticides is more advantageous as it is safer for humans and other organisms indirectly affected, additionally, targets P. fuliginosa directly.[13]