Southern Black Widow Male (Latrodectus mactans)
Jacksonville, Texas, 12 April 2007

This male was found in a smaller web less than fifteen feet from the female. It is not unusual for males of this species to prepare and maintain separate webs, though the males will also cohabit the webs of females.  This specimen has the exterior coloration typical for males of the species, but such coloration is quite variable. Note the string of spots down the centerline of the dorsal abdomen, and the whitish lateral markings on the abdomen sides. Underneath, the sternum (the plate covering the ventral surface of the carapace) is completely black, while the ventral abdomen is marked with a large, reddish orange hourglass. The legs, though mostly black, have intermittent tan sections that appear to follow a somewhat regular pattern.

The hairs on the body of the male are more conspicuous, though they remain sparse in comparison with those of most spiders.

The photo below provides a dorsal view of the male black widow's eyes, showing the PME (center), the structure containing the AME, and the lateral structure containing the right-side PLE and ALE.

A dorsal view of the spider's pedipalps is shown below.  These structures are quite different in the male.  In the female the pedipalps appear as diminutive legs, but in the male of this species they are grossly enlarged at their distal ends. The male palp is used to transfer sperm to the female's epigynum during copulation.  Its unique architecture, for a given species, assists in making precise identifications.  Though such specificity suggests a means whereby cross-breeding between species is discouraged or prevented, strong evidence for that is lacking.  Apparently, cross-breeding is unlikely, not because of the architecture the copulatory organs, but more as a consequence of unique courting rituals.

A ventral view of the male pedipalps shows some details of their gross external features.  The spiral structure in each palp is the embolus, which forms a long, spiral thread whose length can be several times that of the male's body.  It is not unusual for an embolus to break during copulation, and to be left behind when copulation is complete.  Apparently, though such artifacts may remain in the epigynum for lengthy periods, they do not necessarily interfere with future mating.