Courtship and Reproductive Isolation in Two Closely Related Desid Spiders, Badumna longinqua and Badumna insignis (Araneidae: Desidae)

We studied the development and reproductive behavior of two sympatric New Zealand spiders, Badumna longinqua and Badumna insignis (Araneae: Desidae), in the laboratory. Both species have intersexual size dimorphism and, within each species, males vary up to 35-fold in size. Females of B. longinqua produce up to 12 egg sacs, and those of B. insignis produce up to 18 sacs. Clutch size and number of egg sacs is positively correlated with adult female longevity, but not female weight, in both species. Courtship in B. longinqua is longer and entails more acts than in B. insignis. Both species exhibit prolonged copulation. The number of palpal insertions during copulation is not correlated with clutch size, length of sperm storage, female longevity, male weight, or female weight in either species, but number of insertions is positively correlated with relative male weight in B. longinqua and time until first oviposition in B. insignis. The two species do not interbreed in the laboratory. Although theyare similar morphologically, they are reproductively isolated via reproductive behavior; similarities in courtship suggest that the female might use vibratory or chemical cues to assess conspecificity of males.