Evaluation of Secondary Screwworm biology as a proxy for Primary Screwworm

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Life history traits of the Turkestan Cockroach

Turkestan cockroach (Periplaneta lateralis) is an invasive pest well-adapted to dry environments in the Southwestern US. Populations of P. lateralis have expanded in the last 20 years, significantly displacing other roach species, including the oriental cockroach. This range expansion could be driven by life history traits, namely developmental time. In the first experiment, we looked at the developmental time of these pests from first instar to adulthood at two different temperatures, 25°C and 30°C, rearing each cockroach individually in cups. For the second experiment, we reared them in cohorts of 50 for both temperatures. At 25°C, the mean developmental time for the males and females reared under solitary conditions was 214.4 ± 1.16 days and 215.1 ± 1.34 days, respectively, which significantly reduced to 89 ± 0.84 days for males and 94 ± 0.56 days for females under group rearing. At 30°C, the mean developmental time for the males and females reared under solitary conditions was 182.2 ± 2.49 days and 188.8 ± 2.39 days, respectively, which significantly reduced to 73.3 ± 0.745 days for males and 72.0 ± 0.56 days for females under group rearing. This time can be expected to be much faster in states such as California, Nevada, and Arizona, where the summer temperatures can frequently exceed 40°C, allowing multiple generations in a single year. At both temperatures, P.  lateralis reared individually developed from neonate to adult in eight to ten instars, with the most individuals requiring eight or nine molts to develop.  

Figure 1: adult males and females of the Turkestan cockroaches (Periplaneta lateralis)

Figure 2: Individual cups with food and water used for the solitary rearing of P. lateralis