Morphological variability and teratologies in the stag beetle Lucanus cervus (Coleoptera: Lucanidae) from Romania

Abstract

In the present study 423 Lucanus cervus individuals belonging to the entomological collection of the” Grigore Antipa” National Museum of Natural History (MNINGA) were checked for the presence of morphological differences and anomalies. Various malformations were identified in 16 specimens. This study also presents the first cases of bilateral symphysocery 2 + 3 and unilateral symphysocery 2 + 3 + 4 at the antennal clubs for L. cervus, as revealed by scanning electron microscopy. The teratological cases were more prevalent on the left rather than the right antenna (36.3% vs. 18.18%). The normal structural variations in L. cervus were classified as follows: different number of lamellate antennomeres of the antennal club, different number of pores on the last lamella and different shapes of the clypeus. More than 94% of the examined individuals had four antennomeres at the antennal club for both left and right antennae. The rounded shape (72%) with a uniporous sensilla (98%) of the last lamellate antennomere was the most common morph in the analysed samples. Among variations, V-shaped clypeus form was prevalent (37.3%) in L. cervus analysed males. Some structural modifications could have been caused by environmental factors producing alterations in the pupation or eclosion stages. For a better understanding of the causes of teratology and the presence of morphological changes in populations of L. cervus, further investigations are needed.