forcipulas

Forcipulas are a pair of modified appendages found at the posterior end of certain arthropods, most notably in the order Diplopoda, which includes millipedes. These structures are derived from the terminal leg-bearing somites and are typically pincer-like or forceps-like in appearance. The exact form and function of forcipulas can vary significantly between species, but they are generally used for defense, sensing, or reproduction.

In many millipede species, forcipulas serve as defensive weapons. When threatened, the millipede may curl its body and attempt to pinch an attacker with its forcipulas. The force exerted can be surprising, and some species may also secrete defensive chemicals from glands associated with these appendages. In other cases, forcipulas play a role in mating. Males may use them to grasp the female during copulation or to manipulate her body in preparation for mating. The sensory function of forcipulas is also a possibility, with some researchers suggesting they may aid in detecting vibrations or chemical cues in the environment. The morphology of forcipulas can be a useful characteristic for taxonomic identification, helping scientists distinguish between different species and genera of millipedes. Their presence and form are a testament to the diverse evolutionary adaptations found within the arthropod phylum.