3-Methyl-2-hexanone from the triatomine bugDipetalogaster maximus (Uhler) (Heteroptera; Reduviidae)

Abstract

380Compounds 38617, 38650, and 38694 were ineffective even at the 0.5% level. A phytotoxic response was noted at the 0.5% level in onty 2 of the materials, 20702-c and 36313. Although little can be said concerning structure-activity relationships among these compounds, the results suggest that the presence of a methoxy group ortho to the THP group considerably increases the activity of the THP ether of unsubstituted phenol (36235), Even greater improvement is obtained by the presence of a dioxymethylene group on the phenol molecule. Suprisingly, though the THP ether of 3,4-methylenedioxybenzyt alcohol (20702-c) is not derived from a phenol, it proved to be one of the most effective compounds in this series. It was noted that, though the THP ethers of 2-hydroxybenzaldehyde and of 2-hydroxy-5methoxybenzaldehyde are not effective at either concentration, the THP ether of 2-hydroxy-4-methoxybenzaldehyde is highly effective even at the 0.1% level. These data add to the numbers of materials which are promising as feeding deterrents for striped cucumber beetle 5. As the beetle is a significant problem on cucurbits due to both its feeding and transmission of disease, an effective antifeedant would be an attractive alternative to present control tactics. Experientia 39 (I983), Birkh~user Verlag, CH-4010 Basel/SwitzerlandSummary. The occurrence of 3-methyl-2-hexanone as a major component of the secretion and possible alarm substance from the metasternal scent glands in the triatomine bug Dipetalogaster maximus is reported.Dipetalogaster maximus (Uhler) is a very large 33-42 mm long blood sucking (triatomine) bug. It occurs naturally in Mexico at the extreme southern tip of semi-arid California Baja (Sur) z. Trypanosoma cruzi, which causes Chagas' disease in humans, is transmitted by triatomine bugs. Although D. maximus is not, because of its restricted distribution, important as a carrier of T. cruzi 2 the early larval stages are proving useful in xenodiagnosis, as a natural means of detecting T. cruzi in patients suspected of having Chagas' disease 3. In the efforts which continue to be made to secure improvements in the techniques used to detect and control the noxious triatomines searches have been made for behavior modifying chemicals which the insects themselves produce 4. Here we should like to report evidence indicating that 3-methyl-2-hexanone is a major component of the secretion and a possible alarm substance from the metasternat (= metathoracic) scent glands olD. maximus. Materials and methods. Larvae and adults of D. maximus were obtained from Cambridge, England I (the larvae were reared to adulthood in our laboratory, in Cardiff). The metasternal scent glands were isolated by dissection under 200 mM NaC1. They are present only in the adult insect. The electron impact gas chromatographic-mass spectrometric (GC-MS) analyses 1 were carried out using a 7070H VG mass spectrometer at 70 eV with the ion source temperature 190~separator 180~ and 200 ~tA ionizing current. Separations were achieved with a 2 m • 2 mm i.d...

Chemical Communication in the True Bugs and Parasitoid Exploitation

“…The new glands-Brindley's glands (situated laterally under the first abdominal tergite), and the ventral glands (at the junction of the thorax and abdomen)-are both paired glands that are identical in the sexes, and occur either by themselves or coexist with the metathoracic gland (Staddon, 1986). Secretions from Brindley's glands in hematophagous reduviids (Triatominae) often contain isobutyric acid (Blum, 1981), whereas in the lone chemically investigated triatomine having only metathoracic glands, Dipetalogaster maximus, 3-methyl-2-hexanone is the major secretory component (Rossiter and Staddon, 1983).…”

The Sexual Behaviour of Chagas' Disease Vectors: Chemical Signals Mediating Communication between Male and Female Triatomine Bugs

“…The secretion from the metasternal glands contains several compounds, some of which are highly volatile aliphatic ketones and alcohols ( Table 1). The first compound identified from these glands, 3-methyl-2-hexanone, from Dipetalogaster maxima (Uhler, 1894), may function as an alarm pheromone or defensive secretion [36] and can be detected when bugs of this species are disturbed [27]. Volatile components emitted from these glands have now been identified in other triatomine species such as T. infestans, R. prolixus, and T. brasiliensis.…”

Reproductive Biology of Triatoma brasiliensis (Hemiptera, Triatominae) During the Imaginal Molt

“…The transition from the fifth instar nymph to adult is named imaginal molt. During this process it occur some corporal changes, such as the emergence of wings, 2 exocrine glands (metasternal and Brindley's glands) 3,4 and development of the reproductive system.…”