On the Chemical Disguise of a Physogastric Termitophilous Rove Beetle

Inter-specific symbiotic links are often reinforced by morphological, physiological, or behavioural trait modification undergone by the associated species. In some cases, such as in physogastric termitophile staphylinids, such modifications do facilitate the social interaction. Here we inspect chemical traits of the physogastric staphylinid Corotoca melantho (Insecta: Coleoptera) and its termite host Constrictotermes cyphergaster (Insecta: Blattodea: Isoptera), aiming to verify whether staphylinids resemble their host. First, we compared CHC profiles of hosts and guests within and among termitaria, to gather evidence on the origin of such profiles in guests. Then, we examined nitrogen and carbon isotopic signatures of these cohabitants to inspect whether chemical disguise is achieved by predation of host workers by staphylinids. Beetles presented CHC more similar to the CHC of their cohabiting termites than to (i) their conspecifics and (ii) termites from another nest, thereby favouring the hypothesis on CHC acquisition by guests. Isotopic signatures revealed that such similarities could not be majorly determined by share nutrition between these cohabitants. In general, our results evidenced that chemical disguise in termitophiles may function as a strategy for social integration in morphological mimics

Survivorship and walking behavior of Inquilinitermes microcerus (Termitidae: Termitinae) in contact with host workers and walls from host nest

Constrictotermes sp. nests are frequently inhabited by colonies of Inquilinitermes microcerus. In this association, I. microcerus colonies usually establish their colonies spatially isolated from Constrictotermes colonies. Here, we investigated whether the apparent spatial isolation of I. microcerus colonies in Constrictotermes nests should be related to their needs (e.g. feeding) in relation to the central part of the nest or to a possible stress provoked by the presence of the host. For this, survival and walking behavior bioassays were performed to test the hypothesis that the survivorship of inquilines is: (i) reduced in the presence of host, mainly of those from different nests, (ii) increased in contact with inner walls compared with external walls; and that the distance walked and walking velocity of inquiline is: (iii) increased in the presence of the host and (iv) reduced in contact with the internal walls compared with external walls of host nest. The mean time to death of inquiline workers is lower in contact with host (independently from the same or different nest) compared with control and the mean time to death of inquiline workers is lower in contact with external walls of host nest compared with control group and the inner walls. The distance walked and walking velocity of inquiline workers in contact with their hosts (from the same or different nest) did not differ from control, however, these parameters were reduced when workers were in contact with inner and external walls compared with control. In general, our results showed that I. microcerus adopt behavioral strategies to avoid perception by its host

Diet segregation between cohabiting builder and inquiline termite species

How do termite inquilines manage to cohabit termitaria along with the termite builder species? With this in mind, we analysed one of the several strategies that inquilines could use to circumvent conflicts with their hosts, namely, the use of distinct diets. We inspected overlapping patterns for the diets of several cohabiting Neotropical termite species, as inferred from carbon and nitrogen isotopic signatures for termite individuals. Cohabitant communities from distinct termitaria presented overlapping diet spaces, indicating that they exploited similar diets at the regional scale. When such communities were split into their components, full diet segregation could be observed between builders and inquilines, at regional (environment-wide) and local (termitarium) scales. Additionally, diet segregation among inquilines themselves was also observed in the vast majority of inspected termitaria. Inquiline species distribution among termitaria was not random. Environmental-wide diet similarity, coupled with local diet segregation and deterministic inquiline distribution, could denounce interactions for feeding resources. However, inquilines and builders not sharing the same termitarium, and thus not subject to potential conflicts, still exhibited distinct diets. Moreover, the areas of the builder’s diet space and that of its inquilines did not correlate negatively. Accordingly, the diet areas of builders which hosted inquilines were in average as large as the areas of builders hosting no inquilines. Such results indicate the possibility that dietary partitioning by these cohabiting termites was not majorly driven by current interactive constraints. Rather, it seems to be a result of traits previously fixed in the evolutionary past of cohabitants

Cohabitation inquiline-host in termite nests: does it involve distinct mechanisms?

Nests of the termite Constrictotermes sp. can be cohabited by obligatory inquilines Inquilinitermes sp. Recent studies have shown that inquilines establish themselves in mature nests, possibly during the nidification transition phase of the colony (e.g., from the epigeal to the arboreal habit). It is believed that cohabitation is maintained through spatial segregation of the cohabitants since the inquilines aggregate in the central nest region. Here, we described the cohabitation between Inquilinitermes microceus (Silvestri) and a Constrictotermes species in Sergipe, Northeast Brazil. We compared the cohabitation observed in distinct regions considering hypotheses related to the entry and maintenance of the inquiline in the nests. All Constrictotermes sp. nests found in this region are epigeal, unlike already reported in other studies. Approximately 45% of the nests analyzed were associated with I. microcerus, and cohabitation seemed to be dependent on nest size. The entrance of the inquiline was not related to changes in the nidification habit from soil to trees, as suggested in other studies. In addition, inquilines were not associated with and segregated into the dark walls in the central part of the nest. The cohabitation observed here could involve mechanisms which are distinct from the mechanisms reported in other regions

Compartilhamento de ninho entre um cupim hospedeiro e seu inquilino obrigatório

Interações simbióticas ocorrem em todos os grupos de organismos. Este tipo de interação é frequentemente observada em ninhos de insetos socias, no qual a espécie que coabita o ninho junto com o hospedeiro é geralmente outra espécie eusocial. Especificamente para cupins (Isoptera), os mecanismos envolvidos nesta interação permanecem abertos à investigação. Com o intuito de preencher parte desta lacuna, o objetivo desta tese foi analisar aspectos ecológicos e químicos envolvidos na partição de ninho entre o cupim hospedeiro Constrictotermes cyphergaster Silvestri, 1901 (Termitidae: Nasutitermitinae) e seu inquilino obrigatório Inquilinitermes microcerus Silvestri, 1901 (Termitidae: Termitinae). Assim, este estudo fornece evidências sobre como os inquilinos conseguem coabitar o ninho junto com os seus hospedeiros. Os resultados mostraram que a colonização do cupinzeiro pelo inquilino obrigatório está relacionada com o desenvolvimento da colônia hospedeira, o que indica que o inquilino precisa da colônia hospedeira ativa e madura para colonizar os ninhos. Para coexistir no ninho hospedeiro, as espécies inquilinas parecem adotar a estratégia de "evitar conflitos", estabelecendo assim a convivência com o seus hospedeiros no tempo ecológico e evolutivo. Tal estratégia parece ocorrer através de insignificância química da espécie inquilina em seus feromônios de trilha e de alarme. Além disso, foi possível fornecer evidências de que o inquilino obrigatório se beneficia a associação obrigatória entre diferentes espécies de cupins em um mesmo ninho, fornecemos resultados importantes para a biologia geral de cupins, como por exemplo: (i) a primeira análise completa de comunicação de alarme e (ii) importantes características sobre a biologia de inquilino obrigatório I. microcerus, ainda pouco estudada.Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorSymbiotic interactions are spread throughout all groups of organisms. This kind of association is often observed in nest of social insects, in which the guest species are often other eusocial species belonging to the same phylogenetic group of host species. Specifically for termite (Isoptera), the mechanisms behind symbiotic interac- tion among termite species that share a common nest remains open to investigation. Given this gap in the study of nest-sharing in termite, in this thesis we focus on ecological and chemical aspects involved in the nest-sharing among a termite host Constrictotermes cyphergaster Silvestri, 1901 (Termitidae: Nasutitermitinae) and its obligatory inquiline Inquilinitermes microcerus Silvestri, 1901 (Termitidae: Ter- mitinae). In doing so, we aimed to get a better insight about this understudied association, providing evidences on how termite inquilines manage to cohabit the nest along with the termite host species. The results showed that the colonization of termite nest by obligatory inquiline is linked with its host s colony development, which seems to indicate that inquiline needs its host colony active and mature to live in the nest. To live in the nest along with its host colony, inquiline species adopt the conflict-avoidance strategy to establish the coexistence over ecological and evolutionary time. Such conflict-avoidance strategy occurs through chemical insignificance in trail-following and alarm pheromones by inquiline species. In ad- dition, it was possible to provide evidence that inquiline species gains benefit of defense by eavesdropping its host alarm cues. Beyond these insights on termite- termite obligatory association, we provided important findings to termite biology itself, including for instance: (i) the first thorough analysis of termite alarm com- munication and (ii) important biological features of the poorly studied inquiline I. microcerus

Mechanisms of defense in termite nests (Insecta: Isoptera)

Cupins apresentam um elaborado sistema de defesa, porém seus ninhos são frequentemente invadidos por uma variedade de organismos. Os mecanismos que permitem a invasão em cupinzeiros ainda não foram elucidados. Sendo assim, o objetivo desta disserta¸cão foi compreender os mecanismos de defesa em ninhos de cupins. Para isso, levantamos a hipótese que falhas no sistema de defesa podem estar ocorrendo por fator inato ou adquirido, que estaria propiciando a invasão e subsequentemente a coexistência de espécies. Nossos resultados mostraram que (i) espécies com baixa proporção de soldados, fator inato, não propicia a presença de coabitantes, (ii) espécies de cupins com baixa proporção de soldados apresentam operários mais ativos na defesa e que (iii) fatores que ocorrem ao longo da história de vida da colônia geram um descréscimo no sistema de defesa da espécie hospedeira. Desta forma, pode-se concluir que cupins apresentam um balanço entre seus mecanismos de defesa o que propicia maior proteção da colônia, entretanto algumas falhas ocorrem ao longo do ciclo de vida da colônia, permitindo a entrada de invasores e subsequentemente a coexistência de espécies em cupinzeiros.Termites present an elaborated defense system, but their nests are often invaded by a variety of organisms. The mechanisms that allow the invasion in termite nests are not elucidated. So, the objective of this dissertation was to understand the mechanisms of defense in termite nests. To do so, hypothesized that system failures defense may be due to innate or acquired factor, which would be providing the invasion and subsequently the coexistence of species. Our results show that (i) species with low proportion of soldiers, innate factor, not propitiate the presence of cohabitants, (ii) termite species with low proportion of soldiers have more workers active in defense and (iii) factors that occur throughout the life history of the colony lead a decreased in the defense system of the host species. Thus, we can be conclude that termites present a balance between their defense mechanisms which provides greater protection of the colony, however some faults occur throughout the life cycle of the colony, allowing the entry of invaders and subsequently the coexistence of species in termite nest.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Proportion of CHC (%) of termitophile staphylinids Corotoca melantho (ST) and workers of their host termite Constrictotermes cyphergaster (TH)

Inter-specific symbiotic links are often reinforced by morphological, physiological, or behavioural trait modification undergone by the associated species. In some cases, such as in physogastric termitophile staphylinids, such modifications do facilitate the social interaction. Here we inspect chemical traits of the physogastric staphylinid Corotoca melantho (Insecta: Coleoptera) and its termite host Constrictotermes cyphergaster (Insecta: Blattodea: Isoptera), aiming to verify whether staphylinids resemble their host. First, we compared CHC profiles of hosts and guests within and among termitaria, to gather evidence on the origin of such profiles in guests. Then, we examined nitrogen and carbon isotopic signatures of these cohabitants to inspect whether chemical disguise is achieved by predation of host workers by staphylinids. Beetles presented CHC more similar to the CHC of their cohabiting termites than to (i) their conspecifics and (ii) termites from another nest, thereby favouring the hypothesis on CHC acquisition by guests. Isotopic signatures revealed that such similarities could not be majorly determined by share nutrition between these cohabitants. In general, our results evidenced that chemical disguise in termitophiles may function as a strategy for social integration in morphological mimics

Dataset on Substrate-Borne Vibrations of Constrictotermes cyphergaster (Blattodea: Isoptera) Termites

Here we present data on distinct stimuli as elicitors of substrate-borne vibrations performed by groups of termites belonging to the species Constrictotermes cyphergaster (Blattodea: Isoptera: Termitidae: Nasutitermitinae). The study consisted of assays where termite workers and soldiers were exposed to different airborne stimuli and the vibrations thereby elicited were captured by an accelerometer attached under the floor of the arena in which the termites were confined. A video camera was also used as a visual complement. The data provided here contribute to fill a gap currently existing in published datasets on termite communication

Mutual use of trail-following chemical cues by a termite host and its inquiline

Termite nests are often secondarily inhabited by other termite species ( = inquilines) that cohabit with the host. To understand this association, we studied the trail-following behaviour in two Neotropical species, Constrictotermes cyphergaster (Termitidae: Nasutitermitinae) and its obligatory inquiline, Inquilinitermes microcerus (Termitidae: Termitinae). Using behavioural experiments and chemical analyses, we determined that the trail-following pheromone of C. cyphergaster is made of neocembrene and (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol. Although no specific compound was identified in I. microcerus, workers were able to follow the above compounds in behavioural bioassays. Interestingly, in choice tests, C. cyphergaster prefers conspecific over heterospecific trails while I. microcerus shows the converse behaviour. In no-choice tests with whole body extracts, C. cyphergaster showed no preference for, while I. microcerus clearly avoided heterospecific trails. This seems to agree with the hypothesis that trail-following pheromones may shape the cohabitation of C. cyphergaster and I. microcerus and reinforce the idea that their cohabitation is based on conflict-avoiding strategies