Chrysochus auratus, the dogbane beetle, has been erroneously implicated as a pecan defoliator in the early literature. Alternative scenarios suggest other chrysomelid species that may have been responsible for the defoliation

Williams, Charles E

English

ValpoScholar

The Great Lakes Entomologist 
Volume 21 
Number 3 - Fall 1988 Number 3 - Fall 1988 Article 7 
October 1988 
Chrysochus Auratus (Coleoptera: Chrysomelidae) Absolved as 
Pecan Pest 
Charles E. Williams 
Virginia Polytechnic Institute and State University 
Follow this and additional works at: https://scholar.valpo.edu/tgle 
 Part of the Entomology Commons 
Recommended Citation 
Williams, Charles E. 1988. "Chrysochus Auratus (Coleoptera: Chrysomelidae) Absolved as Pecan Pest," 
The Great Lakes Entomologist, vol 21 (3) 
Available at: https://scholar.valpo.edu/tgle/vol21/iss3/7 
This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. 
It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. 
For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 
1988 THE GREAT LAKES ENTOMOLOGIST 127 
CHRYSOCHUS AURATUS (COLEOPTERA: CHRYSOMELIDAE) 

ABSOLVED AS PECAN PEST 

Charles E. Williams' 
ABSTRACT 
Chrysochus auratus, the dogbane beetle, has been erroneously implicated as a pecan 
defoliator in the early literature. Alternative scenarios suggest other chrysomelid species 
that may have been responsible for the defoliation. 
Despite the importance of the host plant to the ecology and life history of phytophagous 
insects, knowledge of host plants for many insects remains fragmentary. Compounding 
this paucity of information are blatantly false host plant records which, despite their 
erroneous nature. are often perpetuated through citation in published works. During a 
recent review of the literature concerning the dogbane beetle, Chrysochus auratus 
Fabricius (Coleoptera: Chrysomelidae), I discovered such a reference. C. auratus was 
reported to have caused extensive defoliation of a pecan grove in northern Georgia during 
the summer of 1904 (Newell and Smith 1905). No information was given describing the 
behavior of t e defoliating insect, condition of the pecan trees, or nature of the plant 
community in the vicinity of the orchard. Moreover, I could find no follow-up to this 
unique occurrence in subsequent literature. This report struck me as odd in two ways. 
First, was it possible that an oligophagous insect such as C. auratus, known to feed 
exclusively upon certain members of the Apocynaceae (dogbanes) and Asclepiadaceae 
(milkweeds) (Weiss and West 1921). successfully attempted an extreme host plant shift 
(pecan, Cal)'a illinoensis, is in the distantly related Juglandaceae) in such a rapid and 
devastating manner? Localized feeding specializations are known among insects (Fox and 
Morrow 1981). but in oligophagous species these usually involve subtle host plant shifts 
either within or among closely related families (see Hsiao 1978). Second, given the 
brilliant. metallic-green coloration f C. auratus, was a misidentification likely? 
This matter could easily be settl d by examining specimens of the pecan defoliator. 
Unfortunately, I found no evidence that Newell and Smith deposited specimens of the 
insect in a museum (or even if they experienced the defoliation first-hand), thus the true 
identity of the pecan defoliator may never be known. However, aspects of the life history 
of C. 
auratus convincingly argue against this species as the perpetrator 
of the pecan grove 
defoliation. First, C. auratus is a univoltine, non-eruptive species and appears to have a 
sporadic distribution even when its host plants are numerous (pers. obs.), similar to the 
distribution of the milkweed leaf beetle, Labidomera clivicollis Kirby (Coleoptera: 
Chrysomelidae), and its host plants (Eickwort 1977). Second, C. auratus rarely, if ever, 
defoliates its host and restricts its feeding primarily to margins of leaves (Weiss and West 
1921). Finally, both the low vagility of adults (pers. obs.) and root-feeding habits of C. 
auratus larvae effectively limit the colonizing ability of this species. Therefore, C. 
'Department of Biology, Virginia Polytechnic Institute and State University. Blacksburg, VA 
24061 
1
Williams: <i>Chrysochus Auratus</i> (Coleoptera: Chrysomelidae) Absolved as
Published by ValpoScholar, 1988
128 THE GREAT LAKES ENTOMOLOGIST Vol. 21, No.3 
auratus must have been present in the pecan grove or its vicinity for some time prior to, 
and after, the defoliation. Published evidence for either case is lacking. 
How might have this apparently erroneous account arisen? The most plausible 
explanations are: (1) a transcriptional error by the authors or an assistant; or (2) 
misidentification o  another metallic-green beetle. In the first case, a substitution of C.
auratus for Diachus auratus Fabricius (Coleoptera: Chrysomelidae) may have been made. 
D. auratus feeds primarily upon willow but has been recorded from several other woody 
plants (Wilcox 1979). It is also metallic-green in color. In the second case, misidentifi­
cation of the metallic-colored eumolpine, Metachroma interruptum Say, a documented 
pecan-feeder (Wilcox 1979), is a possibility. 
Felt ( 190 I) dismissed accounts of C. auratus attacking plants other than its usual hosts 
as erroneous or extreme cases in which the insect attacked a novel host when driven by 
starvation. While I agree it is unlikely that C. auratus will attack plants other than the 
Apocynaceae and Asclepiadaceae, it is doubtful that even starvation would fuel a host 
plant shift to as distant a family as the Juglandaceae. Moreover, if a local extinction of its 
host plant were to occur, it is improbable that C. uratus would be present in the numbers 
necessary to colonize and defoliate a pecan grove. 
ACKNOWLEDGMENTS 
I gratefully acknowledge use of the Bailey B. Pepper Entomology Library, Rutgers 
University, for this endeavor. The constructive comments of an anonymous reviewer 
greatly improved the content of this note. 
LITERATURE CITED 
Eickwort, K. 1977. Population dynamics of a relatively rare species of milkweed beetle (Labido­
mera). Ecology 58:527-538. 
Felt, E. P. 1901. Injurious and other insects of the State of New York. 16th Report of the State 
Entomologist. Bul!. N.Y. State Mus. 7:951-1048. 
Fox, L. R. and R. A. Morrow. 1981. Specialization: species property or local phenomenon? Science 
211:887-893. 
Hsiao, T. H. 1978. Host plant adaptations among geographic popUlations of the Colorado potato 
beetle. Entomo!. Exp. App!. 24:437-447. 
Newell, W. and R. I. Smith. 1905. Insects of the year 1904 in Georgia. U.S. Bureau of Entomol. 
Bull. 52:69-74. 
Weiss, H. B. and E. West. 1921. Notes on the insects of the spreading dogbane, Apocynum 
androsaemifolium L., with a description of a new dogbane midge y Dr. E. P. Felt. Canadian 
Entomol. 53:146-152. 
Wilcox, J. A. 1979. Leaf beetle host plants in northeastern North America. World Natural History 
Publications. Marlton, NJ. 30 pp. 
2
The Great Lakes Entomologist, Vol. 21, No. 3 [1988], Art. 7
https://scholar.valpo.edu/tgle/vol21/iss3/7


\u3ci\u3eChrysochus Auratus\u3c/i\u3e (Coleoptera: Chrysomelidae) Absolved as Pecan Pest

Valparaiso University

The Great Lakes Entomologist Volume 21 Number 3 - Fall 1988 Number 3 - Fall 1988 Article 7 October 1988 Chrysochus Auratus (Coleoptera: Chrysomelidae) Absolved as Pecan Pest Charles E. Williams Virginia Polytechnic Institute and State University Follow this and additional works at: https://scholar.valpo.edu/tgle  Part of the Entomology Commons Recommended Citation Williams, Charles E. 1988. "Chrysochus Auratus (Coleoptera: Chrysomelidae) Absolved as Pecan Pest," The Great Lakes Entomologist, vol 21 (3) Available at: https://scholar.valpo.edu/tgle/vol21/iss3/7 This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 1988 THE GREAT LAKES ENTOMOLOGIST 127 CHRYSOCHUS AURATUS (COLEOPTERA: CHRYSOMELIDAE) ABSOLVED AS PECAN PEST Charles E. Williams' ABSTRACT Chrysochus auratus, the dogbane beetle, has been erroneously implicated as a pecan defoliator in the early literature. Alternative scenarios suggest other chrysomelid species that may have been responsible for the defoliation. Despite the importance of the host plant to the ecology and life history of phytophagous insects, knowledge of host plants for many insects remains fragmentary. Compounding this paucity of information are blatantly false host plant records which, despite their erroneous nature. are often perpetuated through citation in published works. During a recent review of the literature concerning the dogbane beetle, Chrysochus auratus Fabricius (Coleoptera: Chrysomelidae), I discovered such a reference. C. auratus was reported to have caused extensive defoliation of a pecan grove in northern Georgia during the summer of 1904 (Newell and Smith 1905). No information was given describing the behavior of t e defoliating insect, condition of the pecan trees, or nature of the plant community in the vicinity of the orchard. Moreover, I could find no follow-up to this unique occurrence in subsequent literature. This report struck me as odd in two ways. First, was it possible that an oligophagous insect such as C. auratus, known to feed exclusively upon certain members of the Apocynaceae (dogbanes) and Asclepiadaceae (milkweeds) (Weiss and West 1921). successfully attempted an extreme host plant shift (pecan, Cal)'a illinoensis, is in the distantly related Juglandaceae) in such a rapid and devastating manner? Localized feeding specializations are known among insects (Fox and Morrow 1981). but in oligophagous species these usually involve subtle host plant shifts either within or among closely related families (see Hsiao 1978). Second, given the brilliant. metallic-green coloration f C. auratus, was a misidentification likely? This matter could easily be settl d by examining specimens of the pecan defoliator. Unfortunately, I found no evidence that Newell and Smith deposited specimens of the insect in a museum (or even if they experienced the defoliation first-hand), thus the true identity of the pecan defoliator may never be known. However, aspects of the life history of C. auratus convincingly argue against this species as the perpetrator of the pecan grove defoliation. First, C. auratus is a univoltine, non-eruptive species and appears to have a sporadic distribution even when its host plants are numerous (pers. obs.), similar to the distribution of the milkweed leaf beetle, Labidomera clivicollis Kirby (Coleoptera: Chrysomelidae), and its host plants (Eickwort 1977). Second, C. auratus rarely, if ever, defoliates its host and restricts its feeding primarily to margins of leaves (Weiss and West 1921). Finally, both the low vagility of adults (pers. obs.) and root-feeding habits of C. auratus larvae effectively limit the colonizing ability of this species. Therefore, C. 'Department of Biology, Virginia Polytechnic Institute and State University. Blacksburg, VA 24061 1Williams: <i>Chrysochus Auratus</i> (Coleoptera: Chrysomelidae) Absolved asPublished by ValpoScholar, 1988128 THE GREAT LAKES ENTOMOLOGIST Vol. 21, No.3 auratus must have been present in the pecan grove or its vicinity for some time prior to, and after, the defoliation. Published evidence for either case is lacking. How might have this apparently erroneous account arisen? The most plausible explanations are: (1) a transcriptional error by the authors or an assistant; or (2) misidentification o  another metallic-green beetle. In the first case, a substitution of C.auratus for Diachus auratus Fabricius (Coleoptera: Chrysomelidae) may have been made. D. auratus feeds primarily upon willow but has been recorded from several other woody plants (Wilcox 1979). It is also metallic-green in color. In the second case, misidentifi­cation of the metallic-colored eumolpine, Metachroma interruptum Say, a documented pecan-feeder (Wilcox 1979), is a possibility. Felt ( 190 I) dismissed accounts of C. auratus attacking plants other than its usual hosts as erroneous or extreme cases in which the insect attacked a novel host when driven by starvation. While I agree it is unlikely that C. auratus will attack plants other than the Apocynaceae and Asclepiadaceae, it is doubtful that even starvation would fuel a host plant shift to as distant a family as the Juglandaceae. Moreover, if a local extinction of its host plant were to occur, it is improbable that C. uratus would be present in the numbers necessary to colonize and defoliate a pecan grove. ACKNOWLEDGMENTS I gratefully acknowledge use of the Bailey B. Pepper Entomology Library, Rutgers University, for this endeavor. The constructive comments of an anonymous reviewer greatly improved the content of this note. LITERATURE CITED Eickwort, K. 1977. Population dynamics of a relatively rare species of milkweed beetle (Labido­mera). Ecology 58:527-538. Felt, E. P. 1901. Injurious and other insects of the State of New York. 16th Report of the State Entomologist. Bul!. N.Y. State Mus. 7:951-1048. Fox, L. R. and R. A. Morrow. 1981. Specialization: species property or local phenomenon? Science 211:887-893. Hsiao, T. H. 1978. Host plant adaptations among geographic popUlations of the Colorado potato beetle. Entomo!. Exp. App!. 24:437-447. Newell, W. and R. I. Smith. 1905. Insects of the year 1904 in Georgia. U.S. Bureau of Entomol. Bull. 52:69-74. Weiss, H. B. and E. West. 1921. Notes on the insects of the spreading dogbane, Apocynum androsaemifolium L., with a description of a new dogbane midge y Dr. E. P. Felt. Canadian Entomol. 53:146-152. Wilcox, J. A. 1979. Leaf beetle host plants in northeastern North America. World Natural History Publications. Marlton, NJ. 30 pp. 2The Great Lakes Entomologist, Vol. 21, No. 3 [1988], Art. 7https://scholar.valpo.edu/tgle/vol21/iss3/7

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\u3ci\u3eChrysochus Auratus\u3c/i\u3e (Coleoptera: Chrysomelidae) Absolved as Pecan Pest

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