Temperature and food availability differentially affect the production of antimicrobial compounds in oral secretions produced by two species of burying beetle.
Carrion beetles of the subfamily Nicrophorinae search and bury a carcass that they utilize for reproduction. After burial, the carcass is coated with oral secretions that delay its decomposition. Previously, oral secretions of Nicrophorus marginatus were found to show antimicrobial activity, whereas secretion of N. carolinus lacked significant activity. Here, we tested the effects of temperature, sex of the beetle, and food type on the antimicrobial properties of oral secretions of both species. Unlike previous findings, we found that oral secretions of N. carolinus had antimicrobial activity. Temperature had significant effects on the amount of secretion protein. When protein concentrations were standardized to 1 micro/ml, N. marginatus secretions had higher antimicrobial activity at cooler temperatures, while N. carolinus had higher activity at warmer ones. The sex of the beetle did not affect antimicrobial activity for either species. Beetles of both species that were fed whole rats contained more protein in their oral secretions than beetles fed with equally sized pieces of raw ground beef. After standardizing the resulting protein concentrations to 1 microg/ml, antimicrobial activity of oral secretion increased for N. carolinus after rat feeding, but not for N. marginatus. Our results highlight key ecological differences between these closely related species. In addition, they demonstrate the importance of experiments being conducted under varying environmental conditions when evaluating species for potential antimicrobial compounds.
Jacques
Betty J
BJ
Biology Department, The University of Nebraska at Kearney, 905 West 25th Street, Kearney, NE 68849, USA.
Akahane
Shusaku
S
Abe
Michiko
M
Middleton
Wendi
W
Hoback
William W
WW
Shaffer
Julie J
JJ
D000818:Animals; D000890:Anti-Infective Agents / Q000378:metabolism*; D002417:Cattle; D001517:Coleoptera / Q000378:metabolism / Q000502:physiology*; D005260:Female; D005502:Food; D008297:Male; D051381:Rats; D012737:Sex Factors; D013696:Temperature
D000890:Anti-Infective Agents
J Biol Chem. 1999 Apr 2;274(14):9320-6
10092609
Insect Biochem Mol Biol. 2002 Oct;32(10):1295-309
12225920
J Chem Ecol. 2008 May;34(5):575-83
18415061
Philos Trans R Soc Lond B Biol Sci. 1990 Jan 30;326(1237):535-51; discussion 551-3
1969647
J Biol Chem. 2001 Feb 9;276(6):4085-92
11053427
J Chem Ecol. 2004 Apr;30(4):719-29
15260219
Annu Rev Entomol. 1998;43:595-618
15012399
Bacteriol Rev. 1962 Dec;26(4):421-47
16350179