Worker Defensive Behavior Associated with Toxins in the Neotropical Termite Neocapritermes braziliensis (Blattaria, Isoptera, Termitidae, Termitinae)

Involvement of the Salivary Glands in the Suicidal Defensive Behavior of Workers inNeocapritermes opacus(Blattaria, Isoptera, Termitidae)

“…Behavioral bioassays showed that salivary gland autothysis in this species is triggered by a strong physical stimulus, evidencing the occurrence of a threshold for this suicidal behavior. Moreover, similar to N. taracua and N. braziliensis , bursting workers of N. opacus release a fluid secretion through a rupture line located right after the metanotum (Šobotník et al, 2012; Costa-Leonardo et al, 2019 a ). The salivary apparatus and foregut also protruded outside the body.…”

“…Similarly, soldier scarcity occurs in N. taracua (Šobotník et al, 2014), and this caste seems to be less frequent in foraging expeditions of N. braziliensis (Pequeno & Pantoja, 2012). Due to this, it is likely that workers of both species have also developed self-destructive defenses as a response to enemy attack (Šobotník et al, 2012; Costa-Leonardo et al, 2019 a ). Another factor, which probably impacts N. opacus defenses, is the high predation rate by ants, especially N. marginata (Leal & Oliveira, 1995).…”

“…Regarding the defensive mechanisms, salivary glands are widely used by termite soldiers (Prestwich, 1979), which sometimes couple stored chemical compounds with mechanical devices aiming to enhance the damage caused to an opponent (Deligne et al, 1981). Nevertheless, few studies have detailed the use of salivary glands as weapons by termite workers so far (Sands, 1982; Šobotník et al, 2012; Costa-Leonardo et al, 2019 a ), which demands further investigation, especially for taxa whose soldier caste is scarce (e.g. Neocapritermes ) or totally absent (e.g.…”

“…Bourguignon et al (2015) reported that the contents from the crystal and salivary glands of N. taracua workers are mixed and result in highly toxic benzoquinones, which can ultimately cause the death of the opponents (Šobotník et al, 2012). On the other hand, the salivary secretion produced by workers of N. braziliensis displays a rich set of defensive compounds, including neurotoxins and theraphotoxins (Costa-Leonardo et al, 2019 a ).…”

“…According to Lauverjat (1973), the lack of secretory activity was also observed in parietal cells of some grasshoppers and cockroaches. In the case of N. braziliensis workers, no secretory vesicles were observed in this type of cells, even though these individuals are fully capable of bursting their body as a consequence of a salivary gland autothysis (Costa-Leonardo et al, 2019 a ).…”