From nymph to adult: comparative morphology and pre-imaginal development of the stridulation apparatus of selected <i>Platymeris</i> Laporte, 1833 species and their hybrids (Insecta: Hemiptera: Heteroptera: Reduviidae)

Our study investigates the morphological development of the stridulatory apparatus in Platymeris biguttatus, Platymeris rhadamanthus, and their hybrid across different nymphal instars. This is the first study to describe the ontogeny of this structure in Reduviidae, particularly in the context of hybridization between two parental species. The findings provide novel insights into the effects of hybridization on the development and morphology of this structure. Comparative analysis of the stridulitrum characters indicates that the hybrid exhibits distinct elongation of the stridulitrum at all developmental stages. The length-to-width ratio of the hybrid stridulitrum remains consistently higher, particularly between the second and third instars. While P. rhadamanthus maintains a naturally elongated stridulitrum with nearly parallel edges, that of P. biguttatus develops a fusiform shape with tapered ends. The hybrid combines these characters, changing toward extreme elongation without proportional widening. Growth patterns reveal a rapid elongation occurring between the second and third instars, followed by more gradual expansion into the imaginal stage. The prosternal groove depth varies among species, with P. biguttatus and the hybrid showing a more pronounced convexity, potentially influencing stridulatory function. Sensilla coeloconica, present in early instars, disappear in adults, suggesting an ontogenetic shift in sensory roles. Our results suggest that hybridization significantly alters the morphology of the stridulatory apparatus, likely impacting its acoustic properties. These findings highlight the need for further research on the functional implications of the rare hybridization phenomenon in Reduviidae, particularly regarding the role of stridulation in communication and predator deterrence.