Seed bugs

Lygaeidae.

This family is composed of elongate, small to medium-sized bugs (BL 3—15 mm) characterized by a wing membrane with only four or five veins. The antennae and beak are four segmented. Most are drab, but many display reds, yellows, and other bright colors that are doubtlessly apo-sematic in function (Sillen-Tullberg et al. 1982). Polymorphism in wing size occurs; usually the hind pair is atrophied or lost, and the membranous tip of the fore wing may be reduced.

Members of this family feed largely on the mature seeds of various plants, a large number from figs (Ficus) (Slater 1972). The orange- and black-banded milkweed bugs, Oncopeltus, form a conspicuous group (Ojeda 1973). These infest milkweed plants, especially the widespread weed Asclepias curassavica, on the seed pods of which they may be found in clusters (Root and Chaplin 1976). These and Lygaeus (and probably others) feed on many asclepiadaceous plants, which contain cardiac glycosides. The bugs probably sequester these toxic alkaloids for their own protection. Oncopeltus fasciatus (fig 8.2a) is widely cultured as a laboratory animal for research in physiology and other areas (Feir 1974).

Several Central American lygaeids exhibit very strong resemblances to beetles (coleoptery), with shell-like, coreaceous hemielytra, which meet evenly along the midline (Slater 1985). The functional significance of the resemblance is not known.

A few species are crop pests. The infamous chinch bug (Blissus leucopterus-fig. 8.2b) causes considerable damage to rice in Peru. Others are beneficial. The big-eyed bug (Geocoris punctipes) is an efficient predator of red spider mites on cotton plantations.

There are about 450 species of this family in Latin America (Slater 1964).

References

Feir, D. 1974. Oncopeltus fasciatus: A research animal. Ann. Rev. Entomol. 19: 81-96. Ojeda, D. 1973. Contribución al estudio del género Oncopeltus Stál (Hemiptera: Lygaeidae). Rev. Peruana Entomol. 16: 88—94. Root, R. B„ and S. J. Chaplin. 1976. The lifestyles of tropical milkweed bugs, Oncopeltus (Hemiptera: Lygaeidae), utilizing the same hosts. Ecology 57: 132-140. Sillén-Tullberg, B., C. Wiklund, and T. Jarvi. 1982. Aposematic coloration in adults and larvae of Lygaeus equestris and its bearing on Müllerian mimicry: An experimental study on predation on living bugs by the great tit Pants major. Oikos 39: 131 — 136.

Figure 8.2 HETEROPTERANS. (a) Large milkweed bug (Oncopeltus fasciatus, Lygaeidae). (b) Chinch bug (Blissus leucopterus, Lygaeidae). (c) Tarnished plant bug (Lygus lineolaris, Miridae). (d) Lunate flat bug (Dysodius lunatus, Aradidae). (e) Cotton lace bug (Corythucha gossypii, Tingidae).

Slater, J- A. 1964. A catalogue of the Lygaeidae of the world. 2 vols. Univ. Conn. Storrs.

slater, J- A. 1972. Lygaeid bugs (Hemiptera: Lygaeidae) as seed predators of figs. Bio-tropica 4: 145-151. Slater, J- A. 1985. A remarkable new coleopter-oid lygacW from Colombia (Hemiptera: Heteroptera). Int. J. Entomol. 27: 229-234.

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