Monday, 15 November 2004
D0041

Pupal survival of Galerucella spp. (Coleoptera: Chrysomelidae): Effects of soil moisture on eclosion

Bethzayda Matos, bmatos@iastate.edu, Iowa State University, Department of Entomology, Ames, IA and John Obrycki, John.Obrycki@uky.edu, University of Kentucky, Department of Entomology, Lexington, KY.

Several studies have suggested that flood regimens, landscape features, and predatory fauna have inhibited the success of Galerucella spp. released for biological control of purple loosestrife (Lythrum salicaria). In the field, we observed varying numbers of Galerucella spp. in wetter vs drier areas of purple loosestrife infestations. Our objective was to determine if soil moisture affects pupal survival and adult emergence of Galerucella spp. We chose three treatments, 0, 30, and 60% soil moisture. Soil moisture was determined using a ThetaProbe® Soil Moisture Sensor. We used 18 paper cups (16 oz) with 32 ± 0.7 g (mean ± SD) of potting soil mix. Each container had 5 pupae (6 cups of 5 pupae), which were placed at 2 cm deep. The paper cups were covered with clear, plastic cups that were placed upside down to prevent adults from escaping. All the cups were placed in a growth chamber at 24 ±1° C temperature and 16:8 (L:D) photoperiod. The experiment was replicated 3 times. More than 50% of the pupae survived (i. e. adults eclosed) at 0 and 30% soil moisture. No adults eclosed from the 60% soil-moisture treatment. Soil moisture is one factor that may influence generational survival of Galerucella spp. in the field.


Species 1: Coleoptera Chrysomelidae Galerucella
Keywords: purple loosestrife

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