Tensile strength in the cuticle of newly molted cockroaches (Periplaneta americana L.) exposed to ultraviolet radiation (Dictyoptera: Blattaria: Blattidae)

Experiments were conducted on newly molted cockroaches to determine if ultraviolet (UV) irradiation affected tensile strength of the cuticle and curtailed its normal darkening. A 4-h exposure of newly molted cockroaches to 254 nm UV (2820 ergs s−1 cm−2) followed by a 20-h recovery period resulted in a mean tensile strength (660 g/mm2) intermediate between that of newly molted cockroaches (343 g/mm2) and cockroaches allowed to tan normally for 24 h (1614 g/mm2). This indicated that UV exposure of newly molted cockroaches curtailed chemical tanning and normal darkening in the cuticle.