Complex alarm strategy in the most basal termite species

Abstract

Studying basal taxa often allows shedding a light on the evolution of advanced representatives. The most basal termite species, Mastotermes darwiniensis, possesses unique morphological and behavioural traits, of which many remain scarcely studied. For these reasons, we conducted a comprehensive study of the alarm communication in this species and compared its components to behavioural modes described in other termites. In M. darwiniensis, the alarm is communicated by substrate-borne vibrations resulting from vertical vibratory movements. Another similar behaviour consists in longitudinal movements, by which the alarm is delivered to other termites in contact with alerted individual. Both these two behavioural modes could be used in synergy to create complex movements. M. darwiniensis also uses chemical alarm signals produced by labial gland secretion, in contrast to Neoisoptera in which this function is fulfilled exclusively by the frontal gland secretion. Moreover, we demonstrated in M. darwiniensis the presence of a positive feedback mechanism thought to occur exclusively in the crown group Termitidae. This positive feedback consists in both oscillatory movements of alerted individuals in response to alarm signals and release of alarm pheromone by excited soldiers. Our results confirm that M. darwiniensis is a remarkable example of mosaic evolution, as it combines many primitive and advanced features, and its alarm communication clearly belongs to the latter category.

The nature of alarm communication in Constrictotermes cyphergaster (Blattodea: Termitoidea: Termitidae): the integration of chemical and vibroacoustic signals

“…To conclude, termites are eusocial cockroaches ( Lo et al, 2000 ; Inward et al, 2007 ; Cameron et al, 2012 ), and their complex social life made them use more sophisticated means of communication compared to their solitary relatives. Concerning the alarm function, termites and Cryptocercus evolved alarm communication using body vibrations, and the use of alarm pheromones evolved twice among termites, in Mastotermes ( Delattre et al, 2015 ) and in Neoisoptera (present study). Our results demonstrate the dual function of the alarm signalling in C. cyphergaster : In addition to vibratory communication occurring in all termites, the soldier frontal gland secretion contains the alarm pheromone, which is a mixture of abundant [( 1S )-α-pinene, myrcene] and rare [( E )-β-ocimene] monoterpenes, all contributing to the desired function.…”

“…Larger molecules were out from the scope of our work, but several sesquiterpenes and a diterpene were previously identified in C. cyphergaster soldier frontal gland secretion as well (see Baker et al, 1984 ; Azevedo et al, 2006 ). The other case of alarm pheromone presence in termites occurred in Mastotermes , but in contrary to Neoisoptera, the pheromone is benzoquinone produced by the labial glands ( Delattre et al, 2015 ).…”

“…The other component of termite alarm signalling, the vibroacoustic communication by means of substrate-borne vibrations, occurs in all termite species studied so far (see Hager and Kirchner, 2013 ; Howse, 1962 , 1964 , 1965 ; Stuart, 1963 , 1988 ; Kirchner et al, 1994 ; Connétable et al, 1998 , 1999 ; Röhrig et al, 1999 ; Reinhard and Clément, 2002 ; Hertel et al, 2011 ; Delattre et al, 2015 ), as well as in Cryptocercus ( Bell et al, 2007 ), the sister-group of all termites ( Lo et al, 2000 ; Cameron et al, 2012 ). Although other cockroaches are able to perceive the substrate-borne vibration ( Bell et al, 2007 ), the communication through drumming is an evolutionary novelty of Cryptocercus -Termitoidea clade.…”

Attraction and vibration: Effects of previous exposure and type of food resource in the perception of allocolonial odors in termites

“…Vibroacoustic communication is widely diffused among social groups to the emission of warning signals (Hunt & Richard, 2013). In termites, this communication is observed from the most basal groups (Delattre et al, 2015) to the most derived ones (Cristaldo et al, 2015). In addition to alert about risks, vibration in termite is also used during foraging activities to indicate nestmates about the amount of food resources found (Evans et al, 2005).…”

Predator-Prey Interactions and Eavesdropping in Vibrational Communication Networks

“…Alarm signals used to inform members of the group about danger can also be considered as a part of defense behavior. Vibrational signals that function to warn conspecifics have been described in termites (e.g., Rosengaus et al, 1999;Hager and Kirchner, 2013;Delattre et al, 2015) and elephants (O'Connell-Rodwell et al, 2007). At present, it is not clear whether footdrumming alarm signals emitted by many mammals in the presence of a predator are perceived as air-borne sound or substrate vibrations, or both (Randall, 2001(Randall, , 2010.…”