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United States Department of Agriculture

Agricultural Research Service

Title: Pollen Analyses of the Bollweevil Exoskeleton

Authors
item Jones, Gretchen
item Coppedge, James

Submitted to: Palynology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 1, 1997
Publication Date: N/A

Interpretive Summary: All flowering plants produce pollen that can be identified as being produced by a specific plant. Many of these plants are important food sources for insects, some of which are major pests on crops. While feeding, insects become externally contaminated with pollen. Because of pollen#s distinctiveness and durability, it is recognized as an important natural marker. This means that it is possible to identify on what plants these insects fed, based on the pollen found on them. We examined the exterior body of adult boll weevils, a important pest of cotton, to determine if pollen on their body could be used as a marker. This would make the process of insect pollen analysis easier, quicker, and possibly more accurate. Of the 37 boll weevils examined, 22 (58 percent) contained external pollen. Pollen from 29 plant species were identified on the boll weevil bodies. Oak pollen was found most frequently (23 percent). Pollen from plum and black willow were found on 18 percent of the boll weevils. These results show that this method of finding pollen on a boll weevil#s body works well. This method is important in studies to identify plants on which insect pests feed and it contributes in our efforts to effectively control them.

Technical Abstract: Previous pollen analyses of boll weevils, Anthonomus grandis Boheman (Coleoptera: Curculionidae), have been conducted by examining the mid-gut portion of the alimentary canal. In this study, the exoskeletons of five boll weevils were examined using scanning electron microscopy to determine on what part of the exoskeleton pollen might accumulate. Pollen was found mainly on the head region. Forty-three (43) boll weevils were collected from pheromone traps in the Brazos River bottomland, Burleson, Co., Texas between 18 April and 5 June 1994. Five (5) were useless due to fungal growth, leaving 38 boll weevils to be examined for pollen. Pollen was found on 58 percent of the boll weevils examined. A total of 29 floral taxa were identified. Quercus sp. (oak) was found most frequently (23 percent of the samples). Prunus sp. (plum) and Salix nigra (black willow) were both found on 18 percent of the samples. To our knowledge, this is the first time that entomopalynological techniques have been applied to pollen analyses of the exoskeleton of boll weevils. This technique resulted in a faster and easier way to identify pollen on boll weevils. As a result of this research, we believe the feeding behavior of boll weevils can be easily and rapidly ascertained.

Last Modified: 12/18/2014
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