A solitary mud-daubing wasp, &lt;i&gt;Brachymenes dyscherus&lt;/i&gt; (Hymenoptera: Vespidae) fron Brazil with evidence of a life-cyde polyphenism

Evandro Camillo

doi:10.15517/rbt.v47i4.19300

Abstract

Nests ( n=60 ) of a solitary mud-daubing wasp, Brachymenes dyscherus were conected at Fazenda Santa Carlota, Cajuru, Sao Paulo, Brazil ín 1995 and 1996 . The multi-celled mud nests were constructed on the interior walls of abandoned houses in dry and shaded places. Nests were composed of 1 to 4 layers with cens constructed in two paralle! series. The number of cens per nest ranged from 3 to 62. Cells containing prey (larvae of Lepidoptera) numbered fram 4 to 29. B. dyscherus is a uniyoltíne species. Adults emerge from September to December, and nesting talces place at the beginning of the following year; however, the developmental period for some immatures with proloFlged diapause l3.Sted up to 596 days. The total duration of immature stages n nests collected in 1996 was less for males than for females. The sex ratio for the total populatíon was 1 . 5 males: 1 female with males emerging earher than females. A life table was constructed, and details of lhe life cycle of the wasps and parasitoids are presented. The mos! common mOl1ality factors were either endogenous or due 10 Melittobia sp. (Eulophidae) .

Highlights

Abstrad: Nests ( n=60 ) of a solitary mud-daubing wasp, Brachymenes dyscherus were conected at Fazenda Santa Carlota, Cajuru, Sao Paulo, Brazil ín 1995 and 1996
Two parallel rows of cells are constructed from bottom to top, always starting from the CAMILLO: A solitary Brazilian rnud-daubing wasp, Brachymenes dyscherus
As observed here in B. dyscherus, most mud-daubing vespids obtain their mortar for nest construction by drinking water at one place and flying to a site of dry, c1ayey soil where they bite at the ground, regurgitate water, and mix the resulting mud to the proper consistency

Summary

Introduction

Abstrad: Nests ( n=60 ) of a solitary mud-daubing wasp, Brachymenes dyscherus were conected at Fazenda Santa Carlota, Cajuru, Sao Paulo, Brazil ín 1995 and 1996. In Brazil, B. dyscherus dyscherus occurs from the State of Pará to Río Grande do Su1 (Giordani Soika 1990) This species, according to Bertoni ( 19 18, in Giordani Soika 1990), builds its nest with mud on the interior waUs of man-made structures, natural rock walls, or dead trees, Nest dimensions are 40 x 80 mm, and nests exhibit a rough and irregular surface. In addition to specíes that construct their nests with mud or REV ISTADE BIOLOGÍATROPICAL masticated plant material, there are species of Eumeninae that excavate the soil or occupy and modify preexisting cavities (Iwata 1976). The study area contains sorne abandoned buildings surrounded by abandoned orchards, pastures and cultivated land (mainly sugar cane)

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