THE ORB-WEAVER GENERA VERRUCOSA, ACANTHEPEIRA, WAGNERIANA, ACACESIA, WIXIA, SCOLODERUS AND ALPAIDA NORTH OF MEXICO (ARANEAE: ARANEIDAE) HERBERT W. LEVI 1 Abstract. North of Mexico are found one spe-cies each of Verrucosa, Wagneriana, Acacesia, Scoloderus and Alpaida, four species of Acantlie-peira, of which two are new, and three of Wixia, of which one is new. Most species of these genera, except Acantliepeira, are tropical American; the Xearctic species are found in the eastern half of the United States, except that Wixia globosa is found in the Southwest. Morphological intermedi-ates of the Acantliepeira species are found. Among these genera, diversity of habits and web structure is much greater than would be expected from studies based on groups with mainly temperate distributions. INTRODUCTION Most orb-weavers are tropical and in-formation about the few well-known north temperate orb-weavers has been generalized erroneously. Lack of information on tropi-cal species has permitted arachnologists to study web structure only superficially, and there is as much diversity in habits and be-havior as there is in web structure. The tropical orb-weavers tantalize with their promise of exciting behavioral adaptations to be discovered once we know the species. Not only do orb-webs differ in structure, but, more importantly, they differ in when and how they are used. Most species do not share the well-known habits of Araneus diadematus (Witt, et a]., 1968): making a web early in the morning just before day-light, keeping the orb up a day, tearing 1 Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138. down all but the frame lines during the night. Araneus species are generally noc-turnal, but leave their webs up during the day. Acacesia hamata makes its fine-meshed, previously unknown, web at dusk, and hauls it in at daybreak, only to make a new web in a different place the follow-ing evening (Plate 5). Verrucosa arenata makes a large, loose web low in trees each morning or evening and removes it after sunrise; this species rests head up in its web (Plates 1, 2), the reverse of the usual orb-weaver resting position. The Scoloderus web is a long ribbon (Plate 6) with the hub at one end. As it has only recently been found, we may suppose it is a nocturnal web. Other orb-weavers in the tropics pull their webs in only a few hours after completing them (W. Eberhard, per-sonal communication). In Panama I ob-served a large Eriophora sp. female, closely related to the group treated here, making a huge web, about 60 cm diameter, after dark every night. By morning the web had disappeared, and a new one was made the following evening after dark. Not even frame threads were left during the day and the spider itself disappeared. While Ver-rucosa arenata makes a flimsy retreat on a leaf (Plate 1), Acacesia hamata makes no retreat at all but depends on its coloration to make it disappear among foliage (Plate 5). Wixia is believed to make its web high in trees, and the spider probably rests Bull. Mus. Comp. Zool, 147(8): 351-391, February, 1976 351
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