Journal of Chemical Ecology, VoL 7, No. 5, 1981
DEFENSIVE SECRETIONS OF NEW ZEALAND TENEBRIONIDS: I. Presence of Monoterpene Hydrocarbons in the Genus Artystona (Coleoptera, Tenebrionidae)
C. G N A N A S U N D E R A M ,
1 H. Y O U N G , 2 and R . F . N . H U T C H I N S 1
1Entomology Division and 2Division of Horticulture & Processing Department of Scientific & Industrial Research Private Bag, Auckland, New Zealand (Received September 15, 1980; revised January 6, 1981)
Abstract--The defensive secretions of four species of the genus Artystona endemic to New Zealand differ from those of other tenebrionids in that they contain a-pinene and limonene, as well as the more characteristic quinones and alkenes. Adults and larvae ofA. obscura, A. erichsoni, A. rugiceps, and Artystona sp. feed on the lichen Parmotrema reticulatum (Taylor), but the terpenes are not sequestered from it. The defensive secretions of the four species show some interspecific variation.
Key Words--a-Pinene, defensive secretions, interspecific variation, limonene, monoterpenes, pentadecene, Artystona sp., Coleoptera, Tenebrionidae, lichen, Parmotrema reticulatum.
INTRODUCTION
Arthropods have the most diverse chemical defense substances among landdwelling animals, and many of these chemicals have been isolated and identified (Weatherston and Percy, 1970). Except for the defensive secretions of Platyzosteria novaeseelandiae (Benn et al., 1977) and six staphylinids, no work has been done on the defensive exudates of arthropods found in New Zealand. Of the staphylinids investigated, the defensive secretions of Thyreocephalus species found in New Zealand differed from those of the same species found in Australia (Gnanasunderam et al., 1981a) and Tramiathaea cornigera and Thamiaraeafuscicornis contained esters which hitherto had not been identified in the defensive secretion of any other staphylinid 889 0098-0331/81/0900-0889503.00/0 9 1981PlenumPublishingCorporation
890
GNANASUNDERAM ET AL.
(Gnanasunderam et al., 1981b). However, there is a great deal of diversity in the types of chemicals found in the defensive secretions of staphylinids (Duffey, 1976), and it is difficult to discern whether it is this diversity or the environment that has caused the uncharacteristic chemistry of the defensive secretions of the staphylinids found in New Zealand. The defensive secretions of the tenebrionids, however, are more homogenous than those of the staphylinids despite having variations at generic and specific levels. Of the 147 species of tenebrionids studied by Tschinkel (1975), the defensive secretions were predominantly combinations of quinones and 1-alkenes. The study of the defensive secretions of tenebrionids found in New Zealand was undertaken in order to see if they varied in their chemistry from those studied elsewhere. This is the first report in this series. METHODS AND MATERIALS Adults of Artystona erichsoni (Auckland district), A. rugiceps (Noises Islands off the coast of the North Island), A. obscura (Craigieburn State Forest), and Artystona sp. (Central Otago) were collected in the late spring. They were all found on the lichen Parmotrema reticulatum, but no two species were found in the same locality. The defensive secretions of all the beetles were collected on small squares of tissue paper which were subsequently immersed in pentane as described in Gnanasunderam et al. (1981 b). A portion of the total secretion of each species of Artystona was separately chromatographed on 5 • 0.5-cm Florisil columns. The columns were successively eluted with pentane and 5, 10, 20 and 50% (v/v) diethyl ether in pentane (Gnanasunderam et al., 1981b). A fresh sample (100 g) of the lichen P. reticulatum (Taylor) was extracted with ether-pentane (50:50 v/v) and flushed through a (10 • l-cm) Florisil column with pentane. The pentane eluate was then concentrated under a stream of N2 and analyzed by gas chromatography. Gas chromatography was carried out on a Varian 2700 instrument fitted with a flame-ionization detector. Nitrogen was used as the carrier gas. Gas chromatography-mass spectrometry (GC-MS) was performed on a Varian 2700 gas chromatograph coupled via a membrane separator (at 180~ to an AEI-MS30 mass Spectrometer operated at 20 eV for low resolution and 70 eV for high resolution. Helium was used as the carrier gas. Columns used were a 50-m OV-17 SCOT column and 2-m X 2-ram (ID) columns packed with 15% (w/w) OV-17 and 10% (w/w) and Silar 10CP on Chromasorb W - A W - H M D S (100-120 mesh). All columns were temperature programed from 80 to 200~ at 4~ RESULTS Gas chromatogrpahy of the defensive secretions of the four species of
Artystona on the OV-17 SCOT column revealed the presence of two major
TENEBRIONID
891
DEFENSE SECRETIONS
components (B and F) and four minor components (A, D, E, and G) in all four species (Figure 1). Another minor component, C, was absent from Artystona sp. The OV-17 column gave a better separation than the Silar 10CP column. Figure 1 shows differing proportions of the chemicals in each of the four species of Artystona. The gas chromatography of the pentane fraction from the Florisil columns of the defensive secretions revealed the presence of hydrocarbons A, B, F, and G. High-resolution mass spectra of peaks A and B showed a parent ion at m/e 136.1247 (Clo H i 6 = 136.1248). An ion at m/e 121.1023 ( C g H 13 = 121.1014) and the characteristic M-43 of most monoterpenoid spectra at 5O A, rugiceps
A. sp.
4O
*
30" O
v
~ 20"
0
A
B
C
D
F
G
A
B
D
E
G
5O A. obscura
A. erichsoni
4O
~ 3o ~ 20
,o 0
I
I
I
I
A
C
D
E
G
t
~
A
C
D
I
I
E
G
FIG. 1. Composition of the defensive secretions of four species of Artystona. *Percentage peak area of the total peak area of the GC trace on a 15% OV- 17 column (2 m) temperature programed from 80 to 200~ at 4~ (A) a-pinene; (B) limonene; (C) benzoquinone; (D) toluoquinone; (E) ethylquinone; (F) pentadecene; and (G) heptadeeene.
892
GNANASUNDERAM ET AL.
93.0708 (C7H9 = 93.0702) suggested that A and B were monoterpene hydrocarbons. A peak at m/e 68 in the spectra of B further indicated that it was limonene. This fragment is the result of a retro-Diels-Alder rearrangement (Enzel et al., 1972). When A and B were coinjected with a series of monoterpene hydrocarbons the retention time of A coincided with that of c~-pinene and that of B with limonene. These compounds gave mass spectra identical to those of authentic a-pinene and limonene, respectively. Mass spectrometry of F and G gave molecular ions at m/e 210 and 238 and a fragmentation pattern typical of unsaturated 1-alkene. The mass spectra and retention times of F and G were identical with those of 1-pentadecene and 1-heptadecene. GC-MS of the quinone fraction (20% ether-pentane) from the Florisil column established parent ions for C, D, and E at m/e 108, 122, and 136, respectively. All three components (C, D, and E) were shown to have retention times identical to benzoquinone, toluoquinone, and ethylquinone, respectively, by separate coinjection of the quinone fraction with the individual standards. When the pentane fraction of the lichen extract was analyzed by gas chromatography, no ct-pinene or limonene was detected. DISCUSSION
The four species of Artystona investigated are endemic to New Zealand, and belong to the subfamily Tenebrioninae (Watt, 1974). The genus has usually been included in the tribe Cnodalonini, but it is not closely related to typical members of the tribe (J.C. Watt, personal communication). The adults and larvae have been known to hide during the day under loose bark in dead wood and emerge at night to feed on lichen (Watt, 1969). The monoterpene hydrocarbons a-pinene and limonene have not previously been reported from tenebrionid defensive secretions. Although terpenoid compounds have been found in four of the families in the order Coleoptera (Weatherston and Percy, 1978), terpene hydrocarbons have not hitherto been identified in the defensive secretions of any beetle belonging to this order. However, these hydrocarbons are found in other insects, a-Pinene and limonene have been isolated from two species of Hemiptera (Aldrich, 1979) and in the frontal gland exudates of termites of the genus Nasutitermes (Morre, 1964). a-Pinene has also been isolated from the frontal gland of the sawfly Neodiprion sertifer (Eisner et al., 1974). However, the a-pinene in N. sertifer is sequestered from conifers such as Pinus sylverstris on which the larvae feed (Eisner et al., 1974), but, since neither t~-pinene nor limonene are present in the lichen P. reticulatum on which the genus Artystona feeds, these terpene hydrocarbons must be synthesized by the beetles. The limonene and
893
T E N E B R 1 O N I D DEFENSE SECRETIONS
c~-pinene give the defensive secretion of the Artystona species a terpene odor, and the unusual addition of terpenes to the essentially quinone-hydrocarbon defensive secretion is interesting. Tschinkel (1975) suggests that the differences in the defensive secretions of the tenebrionids have evolved in response to different predators and the presence of terpenes in these tenebrionid beetles may also represent an evolutionary response to particular predators. Monoterpene hydrocarbons such as limonene and pinene produced in the frontal gland exudates of termite soldiers are known to form part of a highly effective defensive secretion (Blum, 1978). However, the function of these terpenes in the defensive secretions of the Artystona species will remain in doubt until the ecological relationship of the genus Artystona has been investigated further. By peak area, limonene and pentadecene are the two major constituents in the defensive exudate of the genus A rtystona. Pentadecene is not a common hydrocarbon in the defensive secretion of tenebrionid beetles studied to date as not more than 20 of the 147 species investigated by Tschinkel (1975) contained this C15 hydrocarbon. However, pentadecene is the most abundant compound in the defensive secretion of A. erichsoni, A. rugiceps and Artystona sp. Interspecific variation is not confined to the genus Artystona but has been observed in the defensive secretions of other tenebrionids such as in the genera Platydema, Zadenos, Argoporis, and Blaps (Tschinkel, 1975). Except for the absence of benzoquinone, the defensive secretion of Artystona sp. is very similar to that of A. rugiceps, whereas they differ from the defensive secretions of both A. erichsoni and A. obscura (Figure 1). Taxonomically Artystona sp. may be a geographic variant ofA. rugiceps, and A. erichsoni is more closely related to A. obsura than either of them are to A. rugiceps and Artystona sp. (J.C. Watt, personal communication). This is reflected in the differences in the defensive secretions of the four species of Artystona. However, despite these differences, there is no great diversity in the basic chemical composition of the defensive exudates within this genus, but the presence of a-pinene and limonene in its defensive secretions sets the genus Artystona chemically apart from other tenebrionids.
Acknowledgments--We thank Dr. J.C. Watt for collectingand identifyingthe beetlesand Dr. David Gallowayfor identifyingthe lichen. We are gratefulto Prof. M.H. Benn(Universityof Calgary) for supplyingquinone samples. REFERENCES ALDRICH, J.R., BLUM, M.S., LORD, H.A., EVANS,P.H., and BURKHARD,D.R. 1979. Novel Exocrine secretions from two species of scentless plant bugs (Hemiptera: Rhopalidae) EntomoL Exp. Appl. 26:323-331.
894
GNANASUNDERAM ET AL.
BENN, M.H., HUTCHINS, R.F.N., FOLWELL, R., and Cox, J. 1977. Defensive scent of the black stink-roach. Platyzostera novaeseelandiae. J. Insect Physiol. 23:1-28l - 1284. BLUM~ M.S. 1978. Biochemical defenses of insects, pp. 465-513, in M. Rockstein (ed.). Biochemistry of Insects. Academic Press, New York. DUFFEY, S.S. 1976. Arthropod allomones: Chemical effrontories and antagonists. Proc. Int. Congr. Entomol. Washington 15:323-394. EISNER, T., JOHNESSEE,J.A., and CARREL,J. 1974. Defensive use by an insect of a plant resin. Science 184:996-999. ENZEL, C.R., APPLETON,R.A., and WAHLBERG,I. 1972. Terpenes and terpenoids, pp. 351-385, in G.R. Waller (ed.). Biochemical Application of Mass Spectrometry, John Wiley & Sons, New York. GNANASUNDERAM,C., BUTCHER,C.F., and HUTCnINS, R.F.N. 1981a. Chemistry of the defensive secretions of some New Zealand Rove beetles (Coleoptera: Staphylinidae). J. Insect Biochem. In press. GNANASUNDERAM, C., YOUNG, n., BUTCHER, C.F., and HUTCHINS, R.F.N. 198lb. Ethyl decanoate as a major component in the defensive secretion of two New Zealand Aleocharinae (Staphylinidae) beetles--Tramiathaea cornigera and Thamiaraea fuscicornis. J. Chem. Ecol 7:197-202. MOORE, B.P. 1964. Volatile terpenes from Nasutitermes soldiers (Isoptera: Termitidae). J. Insect Physiol. 10:371-375. TSCHINKEL, W.R. 1975. A comparative study of the chemical defensive system of tenebrionid beetles: Chemistry of the secretions. J. Insect Physiol. 21:753-783. WATT, J.C. 1969. Notes on the natural history of Tenebrionidae (Coleoptera) in Canterbury..IV. Z. Entomol. 4:47-49. WATT, 3.C. 1974. A revised subfamily classification of Tenebrionidae (Coleoptera), N.Z.J. Zool. 4:381-452. WEATHERSTON,J., and PERCY, J.E. 1970. Arthropod defensive secretions, pp. 95-144, in M. Beroza, (ed.). Chemicals Controlling Insect Behavior. Academic Press, New York. WEATHERSTON,J., and PERCY,J.E. 1978. Venoms of Coleoptera, pp. 511-548, in S. Bettini (ed.). Arthropod Venoms Handbook of Pharmacology. Springer Verlag, Heidelberg.
DEFENSIVE SECRETIONS OF NEW ZEALAND TENEBRIONIDS: I. Presence of Monoterpene Hydrocarbons in the Genus Artystona (Coleoptera, Tenebrionidae)
C. G N A N A S U N D E R A M ,
1 H. Y O U N G , 2 and R . F . N . H U T C H I N S 1
1Entomology Division and 2Division of Horticulture & Processing Department of Scientific & Industrial Research Private Bag, Auckland, New Zealand (Received September 15, 1980; revised January 6, 1981)
Abstract--The defensive secretions of four species of the genus Artystona endemic to New Zealand differ from those of other tenebrionids in that they contain a-pinene and limonene, as well as the more characteristic quinones and alkenes. Adults and larvae ofA. obscura, A. erichsoni, A. rugiceps, and Artystona sp. feed on the lichen Parmotrema reticulatum (Taylor), but the terpenes are not sequestered from it. The defensive secretions of the four species show some interspecific variation.
Key Words--a-Pinene, defensive secretions, interspecific variation, limonene, monoterpenes, pentadecene, Artystona sp., Coleoptera, Tenebrionidae, lichen, Parmotrema reticulatum.
INTRODUCTION
Arthropods have the most diverse chemical defense substances among landdwelling animals, and many of these chemicals have been isolated and identified (Weatherston and Percy, 1970). Except for the defensive secretions of Platyzosteria novaeseelandiae (Benn et al., 1977) and six staphylinids, no work has been done on the defensive exudates of arthropods found in New Zealand. Of the staphylinids investigated, the defensive secretions of Thyreocephalus species found in New Zealand differed from those of the same species found in Australia (Gnanasunderam et al., 1981a) and Tramiathaea cornigera and Thamiaraeafuscicornis contained esters which hitherto had not been identified in the defensive secretion of any other staphylinid 889 0098-0331/81/0900-0889503.00/0 9 1981PlenumPublishingCorporation
890
GNANASUNDERAM ET AL.
(Gnanasunderam et al., 1981b). However, there is a great deal of diversity in the types of chemicals found in the defensive secretions of staphylinids (Duffey, 1976), and it is difficult to discern whether it is this diversity or the environment that has caused the uncharacteristic chemistry of the defensive secretions of the staphylinids found in New Zealand. The defensive secretions of the tenebrionids, however, are more homogenous than those of the staphylinids despite having variations at generic and specific levels. Of the 147 species of tenebrionids studied by Tschinkel (1975), the defensive secretions were predominantly combinations of quinones and 1-alkenes. The study of the defensive secretions of tenebrionids found in New Zealand was undertaken in order to see if they varied in their chemistry from those studied elsewhere. This is the first report in this series. METHODS AND MATERIALS Adults of Artystona erichsoni (Auckland district), A. rugiceps (Noises Islands off the coast of the North Island), A. obscura (Craigieburn State Forest), and Artystona sp. (Central Otago) were collected in the late spring. They were all found on the lichen Parmotrema reticulatum, but no two species were found in the same locality. The defensive secretions of all the beetles were collected on small squares of tissue paper which were subsequently immersed in pentane as described in Gnanasunderam et al. (1981 b). A portion of the total secretion of each species of Artystona was separately chromatographed on 5 • 0.5-cm Florisil columns. The columns were successively eluted with pentane and 5, 10, 20 and 50% (v/v) diethyl ether in pentane (Gnanasunderam et al., 1981b). A fresh sample (100 g) of the lichen P. reticulatum (Taylor) was extracted with ether-pentane (50:50 v/v) and flushed through a (10 • l-cm) Florisil column with pentane. The pentane eluate was then concentrated under a stream of N2 and analyzed by gas chromatography. Gas chromatography was carried out on a Varian 2700 instrument fitted with a flame-ionization detector. Nitrogen was used as the carrier gas. Gas chromatography-mass spectrometry (GC-MS) was performed on a Varian 2700 gas chromatograph coupled via a membrane separator (at 180~ to an AEI-MS30 mass Spectrometer operated at 20 eV for low resolution and 70 eV for high resolution. Helium was used as the carrier gas. Columns used were a 50-m OV-17 SCOT column and 2-m X 2-ram (ID) columns packed with 15% (w/w) OV-17 and 10% (w/w) and Silar 10CP on Chromasorb W - A W - H M D S (100-120 mesh). All columns were temperature programed from 80 to 200~ at 4~ RESULTS Gas chromatogrpahy of the defensive secretions of the four species of
Artystona on the OV-17 SCOT column revealed the presence of two major
TENEBRIONID
891
DEFENSE SECRETIONS
components (B and F) and four minor components (A, D, E, and G) in all four species (Figure 1). Another minor component, C, was absent from Artystona sp. The OV-17 column gave a better separation than the Silar 10CP column. Figure 1 shows differing proportions of the chemicals in each of the four species of Artystona. The gas chromatography of the pentane fraction from the Florisil columns of the defensive secretions revealed the presence of hydrocarbons A, B, F, and G. High-resolution mass spectra of peaks A and B showed a parent ion at m/e 136.1247 (Clo H i 6 = 136.1248). An ion at m/e 121.1023 ( C g H 13 = 121.1014) and the characteristic M-43 of most monoterpenoid spectra at 5O A, rugiceps
A. sp.
4O
*
30" O
v
~ 20"
0
A
B
C
D
F
G
A
B
D
E
G
5O A. obscura
A. erichsoni
4O
~ 3o ~ 20
,o 0
I
I
I
I
A
C
D
E
G
t
~
A
C
D
I
I
E
G
FIG. 1. Composition of the defensive secretions of four species of Artystona. *Percentage peak area of the total peak area of the GC trace on a 15% OV- 17 column (2 m) temperature programed from 80 to 200~ at 4~ (A) a-pinene; (B) limonene; (C) benzoquinone; (D) toluoquinone; (E) ethylquinone; (F) pentadecene; and (G) heptadeeene.
892
GNANASUNDERAM ET AL.
93.0708 (C7H9 = 93.0702) suggested that A and B were monoterpene hydrocarbons. A peak at m/e 68 in the spectra of B further indicated that it was limonene. This fragment is the result of a retro-Diels-Alder rearrangement (Enzel et al., 1972). When A and B were coinjected with a series of monoterpene hydrocarbons the retention time of A coincided with that of c~-pinene and that of B with limonene. These compounds gave mass spectra identical to those of authentic a-pinene and limonene, respectively. Mass spectrometry of F and G gave molecular ions at m/e 210 and 238 and a fragmentation pattern typical of unsaturated 1-alkene. The mass spectra and retention times of F and G were identical with those of 1-pentadecene and 1-heptadecene. GC-MS of the quinone fraction (20% ether-pentane) from the Florisil column established parent ions for C, D, and E at m/e 108, 122, and 136, respectively. All three components (C, D, and E) were shown to have retention times identical to benzoquinone, toluoquinone, and ethylquinone, respectively, by separate coinjection of the quinone fraction with the individual standards. When the pentane fraction of the lichen extract was analyzed by gas chromatography, no ct-pinene or limonene was detected. DISCUSSION
The four species of Artystona investigated are endemic to New Zealand, and belong to the subfamily Tenebrioninae (Watt, 1974). The genus has usually been included in the tribe Cnodalonini, but it is not closely related to typical members of the tribe (J.C. Watt, personal communication). The adults and larvae have been known to hide during the day under loose bark in dead wood and emerge at night to feed on lichen (Watt, 1969). The monoterpene hydrocarbons a-pinene and limonene have not previously been reported from tenebrionid defensive secretions. Although terpenoid compounds have been found in four of the families in the order Coleoptera (Weatherston and Percy, 1978), terpene hydrocarbons have not hitherto been identified in the defensive secretions of any beetle belonging to this order. However, these hydrocarbons are found in other insects, a-Pinene and limonene have been isolated from two species of Hemiptera (Aldrich, 1979) and in the frontal gland exudates of termites of the genus Nasutitermes (Morre, 1964). a-Pinene has also been isolated from the frontal gland of the sawfly Neodiprion sertifer (Eisner et al., 1974). However, the a-pinene in N. sertifer is sequestered from conifers such as Pinus sylverstris on which the larvae feed (Eisner et al., 1974), but, since neither t~-pinene nor limonene are present in the lichen P. reticulatum on which the genus Artystona feeds, these terpene hydrocarbons must be synthesized by the beetles. The limonene and
893
T E N E B R 1 O N I D DEFENSE SECRETIONS
c~-pinene give the defensive secretion of the Artystona species a terpene odor, and the unusual addition of terpenes to the essentially quinone-hydrocarbon defensive secretion is interesting. Tschinkel (1975) suggests that the differences in the defensive secretions of the tenebrionids have evolved in response to different predators and the presence of terpenes in these tenebrionid beetles may also represent an evolutionary response to particular predators. Monoterpene hydrocarbons such as limonene and pinene produced in the frontal gland exudates of termite soldiers are known to form part of a highly effective defensive secretion (Blum, 1978). However, the function of these terpenes in the defensive secretions of the Artystona species will remain in doubt until the ecological relationship of the genus Artystona has been investigated further. By peak area, limonene and pentadecene are the two major constituents in the defensive exudate of the genus A rtystona. Pentadecene is not a common hydrocarbon in the defensive secretion of tenebrionid beetles studied to date as not more than 20 of the 147 species investigated by Tschinkel (1975) contained this C15 hydrocarbon. However, pentadecene is the most abundant compound in the defensive secretion of A. erichsoni, A. rugiceps and Artystona sp. Interspecific variation is not confined to the genus Artystona but has been observed in the defensive secretions of other tenebrionids such as in the genera Platydema, Zadenos, Argoporis, and Blaps (Tschinkel, 1975). Except for the absence of benzoquinone, the defensive secretion of Artystona sp. is very similar to that of A. rugiceps, whereas they differ from the defensive secretions of both A. erichsoni and A. obscura (Figure 1). Taxonomically Artystona sp. may be a geographic variant ofA. rugiceps, and A. erichsoni is more closely related to A. obsura than either of them are to A. rugiceps and Artystona sp. (J.C. Watt, personal communication). This is reflected in the differences in the defensive secretions of the four species of Artystona. However, despite these differences, there is no great diversity in the basic chemical composition of the defensive exudates within this genus, but the presence of a-pinene and limonene in its defensive secretions sets the genus Artystona chemically apart from other tenebrionids.
Acknowledgments--We thank Dr. J.C. Watt for collectingand identifyingthe beetlesand Dr. David Gallowayfor identifyingthe lichen. We are gratefulto Prof. M.H. Benn(Universityof Calgary) for supplyingquinone samples. REFERENCES ALDRICH, J.R., BLUM, M.S., LORD, H.A., EVANS,P.H., and BURKHARD,D.R. 1979. Novel Exocrine secretions from two species of scentless plant bugs (Hemiptera: Rhopalidae) EntomoL Exp. Appl. 26:323-331.
894
GNANASUNDERAM ET AL.
BENN, M.H., HUTCHINS, R.F.N., FOLWELL, R., and Cox, J. 1977. Defensive scent of the black stink-roach. Platyzostera novaeseelandiae. J. Insect Physiol. 23:1-28l - 1284. BLUM~ M.S. 1978. Biochemical defenses of insects, pp. 465-513, in M. Rockstein (ed.). Biochemistry of Insects. Academic Press, New York. DUFFEY, S.S. 1976. Arthropod allomones: Chemical effrontories and antagonists. Proc. Int. Congr. Entomol. Washington 15:323-394. EISNER, T., JOHNESSEE,J.A., and CARREL,J. 1974. Defensive use by an insect of a plant resin. Science 184:996-999. ENZEL, C.R., APPLETON,R.A., and WAHLBERG,I. 1972. Terpenes and terpenoids, pp. 351-385, in G.R. Waller (ed.). Biochemical Application of Mass Spectrometry, John Wiley & Sons, New York. GNANASUNDERAM,C., BUTCHER,C.F., and HUTCnINS, R.F.N. 1981a. Chemistry of the defensive secretions of some New Zealand Rove beetles (Coleoptera: Staphylinidae). J. Insect Biochem. In press. GNANASUNDERAM, C., YOUNG, n., BUTCHER, C.F., and HUTCHINS, R.F.N. 198lb. Ethyl decanoate as a major component in the defensive secretion of two New Zealand Aleocharinae (Staphylinidae) beetles--Tramiathaea cornigera and Thamiaraea fuscicornis. J. Chem. Ecol 7:197-202. MOORE, B.P. 1964. Volatile terpenes from Nasutitermes soldiers (Isoptera: Termitidae). J. Insect Physiol. 10:371-375. TSCHINKEL, W.R. 1975. A comparative study of the chemical defensive system of tenebrionid beetles: Chemistry of the secretions. J. Insect Physiol. 21:753-783. WATT, J.C. 1969. Notes on the natural history of Tenebrionidae (Coleoptera) in Canterbury..IV. Z. Entomol. 4:47-49. WATT, 3.C. 1974. A revised subfamily classification of Tenebrionidae (Coleoptera), N.Z.J. Zool. 4:381-452. WEATHERSTON,J., and PERCY, J.E. 1970. Arthropod defensive secretions, pp. 95-144, in M. Beroza, (ed.). Chemicals Controlling Insect Behavior. Academic Press, New York. WEATHERSTON,J., and PERCY,J.E. 1978. Venoms of Coleoptera, pp. 511-548, in S. Bettini (ed.). Arthropod Venoms Handbook of Pharmacology. Springer Verlag, Heidelberg.
