Tuesday, March 9, 2010

How to Raise a Spider Army

Scientists at the USDA-ARS subtropical research station in Weslaco, TX are doing some really cool work developing spiders for biocontrol of ag pests.

They're working with cursorial spiders, which spend their nights running around on plants and their days in improvised silk bivouacs.

These spiders are voracious predators of bug eggs and larvae and can really knock out pests when they reach decent population levels. The scientists found that spiders seemed more deadly on cotton than on maize or soybeans (relative to other predators, such as ants) - and hypothesized that this may be due to the presence of extrafloral nectaries on cotton.

To make a fascinating story short, these spiders drink nectar from flowers and extrafloral nectaries to supplement their buggy diet! They also probably eat yeast (which grows naturally in leaking plant sap and nectar). The availability of these "non-prey foods" allow these spiders to mature faster, live longer and produce more spiderlings when their insect prey is limited. Furthermore, they can respond to the smell of nectar and can even learn to associate novel scents with a sugary reward!

They specifically mentioned that they found spiders associated with coriander, buckwheat and alyssum flowers, but they probably can drink nectar from all kinds of plants. Next, they're gonna try spraying crops with a sugary or yeasty scented spider chow to see if they can attract and maintain populations to help control pests. It's definitely a long shot, as any ecologically-based biocontrol strategy has all the complications and limitations inherent in ecology, but I'll be excited to see what happens.

In the meantime, it's an example of the type of interactions that you hope to take advantage of by planting a diverse, mixed garden surrounded by native plants.

2 comments:

  1. Way cool! Our own garden is awash in wolf spiders during the growing season. The only down side is that it wigs out our arachnaphobic friend. ;)

    Here's one that took me by surprise: http://thecluelessgardeners.blogspot.com/2008/07/what-to-do-while-in-labor.html

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