Morphological and Morphometric Parameters of the Reproductive Organs of Euschistus heros (Hemiptera: Pentatomidae) Treated With a Sublethal Juvenile Hormone Analog

Abstract

The stinkbug Euschistus heros is an important pest of Brazilian agricultural production with increasing importance in the Neotropical region. High reproductive potential and increased risk of resistance to insecticides are determining factors influencing its pest status. This work evaluated the effects of pyriproxyfen on the reproduction and morphological development of the reproductive system of E. heros. Pyriproxyfen was utilized at sublethal concentrations (LC30) in fourth-instar nymphs (N4). Sublethal pyriproxyfen resulted in a reduction in fertility and fecundity of 2 and 12% when only the males were treated, 47 and 53% when only the females were treated, and 32 and 46% when females and males were treated. Basal oocytes were larger and more previtellogenic in newly emerged pyriproxyfen-treated females. The nuclear area of testicular accessory cells shrunk after 10 and 15 days of age in treated insects. Similarly, testicular shape was altered, changing from an ellipsoid to an obpyriform pattern, characterized by hypertrophy of the basal region over time. The apparent area of the organ grew until ten days of age, then shrunk at 15 days of age. In summary, pyriproxyfen treatments disrupted the normal development of N4 of E. heros and diminished the reproductive potential of female and male adults.