An 'Odd' discovery...

James Macklin macklin at ACNATSCI.ORG
Fri Apr 11 09:40:05 CDT 2003

Dear Colleagues,

We have made an interesting discovery here in the Herbarium of the Academy of Natural Sciences in Philadelphia and would like to further our knowledge through input from you. The story behind the discovery is somewhat long -winded but I will be brief. Many of you are aware of our past beetle problems and that we have recently completed an upgrade of our cabinetry and compactor system thanks largely to a BRC grant from NSF. For two years now we have been actively freezing our collection for a period of one week at -20 degrees C (we are about half done). We expected a carry over of some beetles into the new system since we have not frozen all the material. In the last few months we noticed larvae in cabinets where the plant material had been recently frozen. Through discussion with Entomologist colleagues we surmised that the larvae witnessed were likely a product of the thawing process which acts as a wake up call for eggs to hatch. Thus our first question to those in herbaria is have you witnessed this phenomenon in your collections? Next, have any of you tried a cycle of freezing, thawing and then refreezing, and if so, how many days in and out?

The story gets more interesting* We assumed that all the larvae we were seeing were from Cigarette beetles (Lasioderma serricornes) since the adult beetles appear on our traps and, based on what is known of their habits, these animals are implicated as the predominant if not exclusive pest in the herbarium. One of our curatorial assistants took a more careful look at these larvae and noticed that they did not look the same. Our Entomologists confirmed this and as it turns out the most common larvae are of the Odd beetle (Thylodrias contractus). So, our question to other knowledgeable herbarium managers and Entomologists out there is do these 'Odd' beetles like to eat plant material preferentially? The larvae certainly do a good job of devouring the dead Cigarette beetles. Does anyone know a good way to trap out these beetles? So far I have not been able to locate a pheromone lure for the Odd beetle.

Any information would be greatly appreciated. Feel free to reply off list if you wish.



James Macklin Ph. D.
Collection Manager
Botany Department
Biodiversity Research Group
The Academy of Natural Sciences
1900 Benjamin Franklin Parkway
Philadelphia, PA  19103-1195
Phone: (215) 405-5088
FAX: (215) 299-1028
email: macklin at

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