Chemical signals associated with life inhibit necrophoresis in Argentine ants

Abstract

One of the most conspicuous and stereotyped activities of social insects such as ants and honey bees is necrophoresis, the removal of dead colony members from the nest. Previous researchers suggested that decomposition products such as fatty acids trigger necrophoric behavior by ant workers. However, fatty acids elicit both foraging and necrophoric responses, depending on the current nest activities (e.g., feeding or nest maintenance). Furthermore, workers often carry even freshly killed workers (dead for <1 h) to refuse piles before significant decomposition has a chance to occur. Here, we show that the cuticular chemistry of Argentine ant workers, Linepithema humile, undergoes rapid changes after death. When the workers are alive or freshly killed, relatively large amounts of 2 characteristic ant-produced compounds, dolichodial and iridomyrmecin, are present on the ants' cuticle. However, these compounds disappear from the cuticle within about 1 h after death. We demonstrate how this phenomenon supports an alternative mechanism of ant necrophoresis in which the precise recognition and rapid removal of dead nestmates are elicited by the disappearance of these chemical signals associated with life.

Burial behaviour by dealates of the termite Pseudacanthotermes spiniger (Termitidae, Macrotermitinae) induced by chemical signals from termite corpses

“…Recently, Choe et al (2009) reported in the Argentine ant Linepithema humile, that the necrophoric behaviour was triggered, not only by the presence of products of decomposition, but also by the rapid disparition of two compounds only produced by live ants, dolichodial and iridomyrmecin. In P. spiniger, our observations showed that the burial behaviour of dealates did not start before 12 h following the death of individuals.…”

“…To prevent prolonged contact between dead and healthy individuals, cadaver removal has been described as an important hygienic behaviour in ants (Wilson et al, 1958;Haskins and Haskins, 1974;Howard and Tschinkel, 1976;Ataya and Lenoir, 1984;Lopez-Riquelme et al, 2006;Choe et al, 2009;Diez et al, 2011;Renucci et al, 2011), bees (Visscher, 1983;Arathi et al, 2000;Purnamadjaja and Russell, 2005) and termites (Mjöberg, 1920;Grassé, 1982;Su, 1982;Pearce, 1987;Chouvenc and Su, 2010). The hygienic behaviour is usually performed by the worker castes (Crosland et al, 1997;Trumbo and Robinson 1997;Hart and Ratnieks, 2002;Wilson-Rich et al 2007;Rosengaus et al, 2011) in long-lived and mature colonies.…”

Beetles Do It Differently: Two Stereodivergent Cyclisation Modes in Iridoid‐Producing Leaf‐Beetle Larvae

“…For work-up, diethyl ether was added, and the solution was washed with brine and dried over Na 2 SO 4 . The crude product was purified by chromatography on silica gel with petroleum ether/diethyl ether ( 4 (447 mg, 11.8 mmol) in dry diethyl ether (40 mL), The mixture was stirred for 30 min at room temperature, and a solution of deuterated ethyl 8-hydroxy-3,7-dimethylocta-2,6-dienoate (400 mg, 1.8 mmol) in dry diethyl ether (10 mL) was added dropwise.…”

“…Plagiodial (2) and plagiolactone are typical for the larvae of Plagiodera versicolora and Linaeidea aenea, and 2 was also found in Prasocuris phellandrii, Phratora laticollis and Phratora vulgatissima. Larvae of P. vulgatissima show, in addition to 2, a low amount of 1 (Table 1).…”

“…Dolichodial (4) and iridomyrmecin (5) are components in the blend of the Argentine ant Iridomyrmex, which suppress the necrotrophoretic behaviour of nestmates. [2] Actinidin (6) is produced by Iridomyrmex nitidiceps, [3] and this has a powerful repelling effect on their predators. All these compounds share a common biosynthetic origin, and their biosyntheses proceeds in plants and insects along the same principal pathway, outlined in Scheme 2.…”