Entomological Identification of the Origin of Imported Cannabis

0Forensic Science Society

ORIGINAL PAPERS

1986

Entomological Identification of the Origin of Imported Cannabis TK CROSBY, JC WATT

Entomology Division, Department of ScientiJic and Industrial Research, Private Bag, Auckland, New Zealand and A C KISTEMAKER, PE NELSON"

Chemistry Division, Department of ScientiJic and Industrial Research, PO Box 2224, Auckland, New Zealand Abstract Chemical methods have proved unsatisfactory for identifying the origin of cannabis plant material imported into New Zealand. However, the identification of insects intimately associated with the cannabis can allow the exact location of the origin. The circumstances of the successful use of this approach to prove the importation of cannabis plant into New Zealand are described. Key Words: Insects in cannabis; Proof of cannabis importation; Cannabis origin. Journal of the Forensic Science Society 1986; 26: 35-44 Received 26 September 1984 Introduction Early in 1982, two separate seizures of cannabis plant material were made by the New Zealand Police. The first involved 188 kilograms, packed in 12 suitcases, and was located in an airport customs bond store. The second arose when a suspect was apprehended with 1.75 kilograms of cannabis plant in his car, and two further packages containing 1.9 kilograms and 3.25 kilograms of cannabis plant respectively were located buried at the suspect's address. The latter three portions of cannabis plant were respectively identified by police exhibit numbers 6, 7 and 9. Subsequent police investigation implicated three suspects in an operation importing cannabis plant from the so-called "golden triangle" region of Burma, Thailand and Malaysia. To support charges of importation, it was essential to prove that the cannabis plant located in the possession of one of the suspects was, in fact, imported and it was also highly desirable to prove the origin. * Author to whom correspondence should be addressed. 35

The identification of cannabis plant for law enforcement purposes is a relatively simple procedure. In major cases involving cannabis, however, it is frequently essential to be able to prove the geographic origin of the sample to prove importation. There is arguably no botanical difference in cannabis plants of differing geographic origin [ I , 21. Numerous chemical attempts have been made to classify cannabis, mainly as a function of its drug and fibre qualities [2,3]. These chemical attempts at classification have mainly involved chromatographic procedures with methods entailing the determination by gas-liquid chromatography (GLC) of the ratios of cannabidiol, tetrahydrocannabinol and cannabinol [2-61, the determination of headspace volatiles by GLC [7], and the determination of the "fingerprint profile" of nonpolar marijuana constituents by high resolution (capillary column) GLC [8]. Various comparisons between high performance liquid chromatography (HPLC) and GLC have also been made [9-121. There are, however, serious limitations to the various chromatographic approaches. The amount of the major cannabinoids produced is dependent upon properties inherited from the seed for several plant generations [13,14]. Other limitations include variation in cannabinoid content during growth of a plant [3,15], and the effects of plant processing and storage [16]. Data on the chemical composition of New Zealand-grown and known imported cannabis plant were obtained by packed column GLC and by HPLC in an attempt to indicate origin, but were unpromising. As a result, a different approach was taken, and biologists were consulted to determine the possibility of identifying extraneous flora or fauna that were foreign to New Zealand, amongst the seized material. This approach proved highly successful. In the importation of cannabis plant described here, insects were found and identified that pinpointed the geographic origin of one of the seizures to within 500 kilometres of Bangkok in South-East Asia.

Experimental The samples of cannabis were qualitatively identified using the conventional techniques of microscopy, the extended Duquenois test and thin layer chromatography [17]. Six samples were taken at random from the 188 kilogram seizure of cannabis plant, and a representative sampie was taken from each of exhibits 6 and 7. Quantitative measurements were made by continuous soxhlet extraction with 40-60 petroleum ether to determine the soluble resin content of the sample, and the A9-THC content was determined by GLC using a Tracor 660 instrument fitted with a 2 m x 4 mm I D glass OV1 column at 230°C. Detection was by flame ionization. Various searching procedures were used to locate insects, including examining the dross, sieving the plant material into various particle sizes and breaking up highly resinous parts of the plant material. Each approach had some 36

success, but care and patience was the prime requirement as the insects found were mainly pinhead size. For identification, the insects were mounted and photographed using scanning electron microscopy. The specimens were not silver- or gold-coated for this purpose, which is the norm for identification quality photographs, as it was felt necessary to retain the insects in the state in which they were found. Results and discussion The soluble resin and A~-THCcontent of the samples analysed are given in Table 1. These results showed significant variations both within and between the three sets of samples. These levels also fall within the range of levels found in New Zealand-grown cannabis plant, and thus no opinion can be formed as to a possible common origin or sou.rce of the suspect plant material. Only passing consideration was given to the use of cannabinoid ratios to give phenotype classification [2-61, as data for New Zealand-grown cannabis was not available, and the entomological approach proved highly successful. TABLE

1. Analysis of seized material

Sample

Petroleum solubles (%)

cannabis

A9-THC

(%)

Ex 188 kg 1

2 3 4 5 6 Ex car Exhibit 6 Ex drum Exhibit 7

Sixty dead insect specimens were collected from exhibits 6, 7 and 9 (Table 2) and of these, only the rice weevil, Sitophilus oryzae (in exhibit 7), has been found in New Zealand [18]. This beetle is cosmopolitan in distribution, and is a stored product pest of rice, wheat, maize, barley and other grains, as well as the products derived from them. It is unlikely that this specimen had infested the plant material after it was imported into New Zealand. None of the remaining 59 specimens found was a New Zealand species. Eight of these specimens provided sufficient information to indicate very strongly the geographic area, and the environment, where the cannabis plant

TABLE 2. Insects and other specimens found in seized cannabis material exhibits 6, 7 and 9 Specimens Insecta Coleoptera(beetles)

Diptera (flies)

Hemiptera (bugs and leafhoppers)

Exhibit

Bruchidius mendosus (Gyllenhall)* Carabidae Tachys (Tachyura) sp.* Chrysomelidae Larval head capsule Corylophidae Arthrolips sp. Sericoderus sp. Unidentified genus Curculionidae Sitophilus oryzae (L.) Beridinae Elateridae Languriidae Loberus sp. Lathridiidae Corticarina sp. Corticarina sp. Melandryidae Nitidulidae Haptoncus sp. Phalacridae Olibrus sp. Hypothenemus areccae Scolytidae (Hornung) Xylocleptes sp. Staphylinidae Stenus basicornis Kraatz* Unidentified genus Tenebrionidae Azarelius sculpticollis Fairmaire* Gonocnemis minutus Pic* Throscidae Triaxagus sp. Damaged specimens and fragments

Number of specimens

Bruchidae

Culicidae Unidentified fragments

9

7 9 6 7 6 9 9 6

Cicadellidae Lygaeidae Agaonidae

Head and prothorax New genus and species Hymenoptera (bees Purapristina verticellata (Waterston)* and wasps) Chalcididae Tropimerus monodon Bc Encyrtidae unidentified genus Pheidologeton diversus Formicidae (Jerdon)* Caterpillars and skin Lepidoptera (moths Noctuidae Yponomeutidae Pupal skin and butterflies) Pscoptera (booklice) Pachytroctidae Tapinella sp. Arachnida Araneae (spiders) Unidentifiable fragments

* These insects were of particular significance in determining the origin of the cannabis plant. 38

was harvested. Two were found in exhibit 6 (1.75 kilograms of plant seized from the car). The wasp Tropimerus monodon, described by BouEek [19] is found only in the South-East Asia region, from north-west India to Sumbawa in Indonesia, and the beetle, Gonocnemis minutus lives as a guest in the nests of termites [20]. One of the eight specimens was found in exhibit 7, the package containing 1-9kilograms of plant located in a drum. This was the carabid beetle, Tachys sp., of an abundant tropical genus whose habitat is predominantly along the banks of streams or lakes [21]. The specimen found is not a species known in Australia (Moore, personal communication).

FIGURE 1 Two of the insects recovered from cannabis plant material, exhibit 9. (a) The beetle, Azarelius sculpticollis; (b) the ant, Pheidologeton diversus. 39

Five of the specimens were found in exhibit 9, the package containing 3.25 kilograms of plant located in a drum. The beetle, Azarelius sculpticollis (Figure la) is a rarely collected species, known only from Sumatra and Burma. The Burmese specimen in the British Museum (Natural History) London, was collected from Burma in the division of Tenasserim [20,22]. Like the related beetle G. minutus, found in exhibit 6, it lives as a "guest" in termite nests. The ant, Pheidologeton diversus (Figure lb), is restricted in distribution to South-East Asia from India to Indochina including Singapore and West Indonesia. It is most common in the Indo-Malayan region, including Thailand (Taylor, personal communication). There is some doubt about records for P. diversus in India [23-251. The specimen found in this instance, however, agreed with the description given by Bingham [23] who stated of P. diuersus, inter alia, that his house in Moulmein, South-East Burma was "periodically invaded by large swarms"; that the bites of the minor workers "are vicious and to be remembered"; and ". . they become a terrible nuisance. In the Thaungyin Valley, Tenasserim (Burma-Thailand border), I know of a Karen village that had absolutely to shift because of the ants." Two other beetles, Stenus basicornis [26] and Bruchidius mendosus [27] are also distributed throughout South-East Asia, although B. mendosus is not known from Indonesia or the southern tip of the Malayan Penninsula. S. basicornis, like Tachys sp., has a habitat predominantly on stream or lake banks. The fifth insect of significance found in exhibit 9 was the wasp Parapristina verticellata [28]. According to Corner [29] P. verticellata is a pollinator of the fig, Ficus microcarpa Linn.f., which is distributed throughout the Indo-Australian region from India and South China to New Caledonia. The beetle A. sculpticollis and the ant P. diversus have been collected from the Tenasserim district of South Burma. A. sculpticollis is a rare species, and has only been collected in this region and in Sumatra. P. diversus has been collected elsewhere, but has been reported in this region in vast numbers. B. mendosus has been collected throughout Southeast Asia, except for Indonesia and Southern Malaysia. The distribution of the other specimens discussed above includes this area. From a plot of the distributions of these three species, it is seen that the South BurmaIIndo-Malayan region is the only area of South-East Asia where they overlap (Figure 2). As P. diuersus has been reported to be very common in the Tenasserim region, this is considered to be the likely origin of the cannabis. Tenasserim is on the western side of the northern part of the Indo-Malayan peninsula; its western border is the Andaman Sea, and its eastern border, Thailand. The Thai capital, Bangkok is about 200 km to the east and the Burmese capital, Rangoon, about 400 km to the northwest. 40

The habitat of the species found indicate that the area from which the cannabis was harvested was adjacent to a stream or lake; that fig trees and termite nests were nearby, and that ants capable of discouraging human habitation were present. It is tempting to speculate that a field study by entomologists in the region indicated may be even more exact in pinpointing the location which this cannabis was grown. From the bulk seizure of 188 kilograms, a portion of about 500 grams only was searched. Six specimens were collected, of which four were identified as being of the order Coleoptera (beetles), as follows: CoccinellidaePullus sp. ; Corylophidae-Orthoperus sp. ; Lathridiidae-Corticarina sp. ; and Scolytidae-Hypothenemus sp. The remaining two specimens were fragmentary and not identifiable. Of these specimens, none is found in New Zealand, and the Hypothenemus sp. is exclusively tropical. The effort put into the collection and identification of specimens from this sample was less than that employed with the other samples, as proof of importation and source existed in the form of airline documentation.

Conclusion The use of entomological expertise successfully proved both the importation and the origin of cannabis plant seized into New Zealand. The procedure, although painstaking, can provide much more information that can be provided by chemical means. A search of the literature indicated that this approach to forensic investigations into the importation of cannabis plant has perhaps been overlooked, as only one reference was found relating to the identification of insects associated with Cannabis sativa 1301. The success of this investigation stemmed from the availability of a division of specialist entomologists within the same government scientific department as the Chemistry Division responsible for the Forensic Services in New Zealand.

Acknowledgements Systematics Section, Entomology Division, DSIR, Auckland, Prof. R A Beaver, University of the South Pacific, Suva, Fiji, Dr Z BouEek, CIE. London, England, Dr J Decelle, Mu5Ce Royal dc I'Afrique Centrale, Tervuren, Belgium, Mr PM Hammond, BMNH, London, England, Miss CMF von Hayek, BMNH, London, England, Dr Z Kaszab, Termeszettudomanyi Muzeum, Budapest, Hungary, Dr M Malipatil, Northern Territory Museum, Darwin, Australia, Dr BP Moore, CSIKO, Canberra, Australia, Dr TR New, La Trobe University, Bundoora, Australia, Dr R D Pope, BMNH, London, England, Dr V Putz, Limnologische Flussstation, Schlitz, West Germany, Dr T Sengupta, Zoological Survey of India, Calcutta, India, Dr RW Taylor, CSIRO, Canberra, Australia, Dr JT Wiebes, Rijksuniversiteit Leiden, Leiden, Netherlands.

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