Ducts in the Gonossiculus of Dendrocerus leucopidis (Muesebeck 1959)
One of the most useful ways to distinguish between different species of ceraphronoid wasps is by looking at the male genitalia. Male and female genitalia fit together like a lock and key, but only between members of the same species. Just as a specific key can only fit a certain type of lock, the male genitalia of one species can only fit the female genitalia of the same species. This helps to ensure that males will only mate with females with whom they can produce offspring.
While looking at the male genitalia of Dendrocerus leucopidis, we discovered tiny channels running through the gonossiculus, a rounded apical structure of the volsella with tooth-like projections that is located next to the penile valve. Upon taking a second look, we noticed that one channel ran to the tip of each tooth-like projection, shown in the picture below.
What do these ducts do? Are they connected to a putative exocrine gland? Unfortunately, so little is known about these wasps that we don’t even know what the gonossiculus is used for during copulation.
In D. leucopidis, the gonossiculus has tooth-like projections that face outward. One possible function of this could be to damage the female genitalia and prevent (or at least discourage) the female from successfully re-mating with another male.
In other species, the gonossiculus is pressed closely against the penis valve. The musculature seems to suggest that the gonossiculus could have a pumping motion, and a possible explanation put forth by Mikó et. al. (2013) is that the gonossiculus may assist in ejaculation.
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