Gender Determination

To decide the gender of a beetle requires a very close look with a lens or microscope.

The macro setting on your camera will often be enough to give you a good look.

Paropsines are only very slightly sexially dimorphic in most cases.

Dimorphism is most strong in three species of Paropsis and not in Paropsisterna; P. deLittlei, P. intermedia and P. dilatata.

Males can be slightly smaller than females and have longer antennae.

The most reliable method of determining gender is to check the four anterior proximal tarsal segments.

In English, that means the first (closest to body) part of the foot. This is not including the back pair of legs. They are dilated (enlarged) in the males. The back pair of legs have narrow anterior tarsal segments in males and females are narrow on all six feet.

This modification is important to assist the male in holding the rotund female during mating. See fig 1.

This 'pad' has very fine hairs, shorter and flat in the middle, moist for hydrogen bonding, as some lizards, such a geckos have. The longer surrounding hairs form an efficient suction mechanism.

As only four legs are used to hold the female, the rear pair have 'normal' non dilated segments.

Fig 1. Paropsisterna crocata.

Fig 2 The male first tarsal segment is dilated Fig 3 the corresponding tarsal segment in females is narrow.

The beetle tarsus (foot) has five segments end to end and ALSO two claws on the distal end. The first tarsal segment (nearest to the body; proximal) is wide only in the male. It is narrow, often parted, with a central line, in the female and also the rear pair of legs in the male.

NOTE: The BI-LOBED segment is distal (near the claw) and is NOT the segment we are referring to.

<BEETLE> Closer is called PROXIMAL; .............. . further away is called DISTAL

anterior/posterior refer to front/back