
The ability of this species to defend itself with a particularly odiferous secretion was reported as early as 1835, when Gray in describing the genus quoted an account by Thomas Say "...that when taken they discharged a milky fluid from two pores of the thorax, diffusing a strong odor..." Albert (1947) also described it as a "...rather thick, tenacious white material..." Blatchley (1920) described it as having "...a peculiar, though somewhat pleasing odor, which has been likened to that of the common everlasting, Gnaphalium obtusifolium L." MacAtee (191

reported a second hand report "...that Anisomorpha buprestoides discharges a vapor from the end of the abdomen and that the discharge is preceded by a peculiar crepidation..." He noted, correctly, that this report differs from almost all others.
Eisner (1965) reported, "The secretion is produced and stored in two elongate, sac-like glands situated in the thorax and opening just behind the head." Happ et al. (1966) presented detailed information on the structure of the glands. The glands open in notches at the anterolateral angles of the pronotum (Littig 1942). The glands are functional from birth and Eisner (1965) reported newly-hatched nymphs successfully repelling attacks by single ants. Meinwald et al. (1962) identified the active ingredient as a terpene dialdehyde related to catnip and named it anisomorphal.
pronotal gland
Eisner (1965) reported that the stick insects generally discharged the secretion as a result of certain perceived threats. They can aim up to 30 to 40 cm with accuracy: "Anisomorpha discharges instantly in response to mild traumatic stimulation as, for example, when individual legs are pinched with forceps, or when the body is tapped or persistently prodded . . . Marksmanship is precise: the spray invariably drenches the particular instrument used for stimulation." Although most discharges required actual physical contact, Eisner (1965) found that the stick insects often would discharge at birds before being contacted by the bird. In trials, Eisner (1965) found the secretion to be an effective defense against ants, beetles, mice and birds; mouse- opossums (Marmosa sp.), however, managed to withstand the spray and consume the stick insect once its reservoir was depleted after up to five discharges from the larger females. One to two weeks are required to replenish the depleted reservoirs (Eisner 1965). Carlberg (1985) found that rats (Rattus norvegicus (Berkenhout)) initially were repelled, but some individuals managed to overcome the defense in subsequent attacks.