O. P-Cambridge, 1889
O. P-Cambridge, 1890
They spin small webs from which they hang upside down and attract male moths that fly into a basket formed by their legs. They use a moth pheromone for this, which resembles the one used by the Bolas spiders Mastophora. The two genera are not closely related, although they belong to the same family. Thus, the same moth catching behavior must have evolved independently in the two genera.
All species are pale yellow-white with scattered, small, white, brown and black random spots, or in some species transverse bands. Females have a body length of about four to ten millimeters. Males are less than half the size of females and less pigmented.
Kaira specimens are uncommon in arachnologist collections, and the females of different species are difficult to separate. Females and immatures can be confused with species of the not closely related genus Pozonia.
When a fly was put into a jar containing a K. alba, the female dropped from the underside of the lid on what seemed a single thread about 12 mm (0.5 inch) long and hung there until the fly blundered into her. Then she clamped her legs around it and killed it. Instead of constructing orb webs, they construct a small trapezoidal web, containing two triangular zigzags of threads, which is remade every twenty minutes. The spider then hangs upside-down by the fourth leg on the lower and shorter parallel edge of the trapezoid, which is spread by the other legs. When a moth flies into the basket formed by the spider's legs, it is clasped and bitten, and later wrapped in araneid-like fashion. The moth is then hung from a trapeze line between the last legs of the spider, which resumes the hunting posture. As many as eight moths can be caught in this way before the spider starts feeding.
- Kaira alba (Hentz, 1850) (Virginia to Mexico)
- Kaira altiventer O. P.-Cambridge, 1889 (southern Texas to southern Brazil)
- Kaira candidissima (Mello-Leitão, 1941) (Argentina)
- Kaira cobimcha Levi, 1993 (Brazil)
- Kaira conica Gerschman & Schiapelli, 1948 (Brazil, Argentina)
- Kaira dianae Levi, 1993 (Peru)
- Kaira echinus (Simon, 1897) (Brazil, Argentina)
- Kaira electa (Keyserling, 1883) (Brazil)
- Kaira erwini Levi, 1993 (Peru)
- Kaira gibberosa O. P.-Cambridge, 1890 (Mexico to southern Brazil)
- Kaira hiteae Levi, 1977 (southeastern USA)
- Kaira levii Alayón, 1993 (Cuba)
- Kaira sabino Levi, 1977 (Southern Arizona)
- Kaira sexta (Chamberlin, 1916) (Guatemala to Brazil)
- Kaira shinguito Levi, 1993 (Peru)
- Kaira tulua Levi, 1993 (Colombia)
- Levi 1993