Papers by Paulo Cristaldo
Resource can regulate animal foraging range, which in turn determines the chances of species co-o... more Resource can regulate animal foraging range, which in turn determines the chances of species co-occurrence. Here, we addressed the question of whether resource determines the co-occurrence of soil-forager termite species (i.e. those foraging in subterranean tunnels). Eight quadrats (4 × 4 m) were marked in seven sites of Brazilian Atlantic rainforests, giving a total area sampled of 896 m 2 . Inside each quadrat, we measured the co-occurrence of soil forager species and the resource suitability (N:C ratio of the soil and litter biomass). The number of records of more than one soil-forager termite species at a single foraging spot, relative to the total number of foraging spots detected in each forest, was taken as a surrogate for spatial co-occurrence. We tested whether termite co-occurrence was mediated by random or nonrandom processes. Data were subjected to linear regression to test how the termite species co-occurrence responds to resources. We compared this method with a null model analysis. Soil-forager termites comprised 885 records, 20 species and 14 genera. From those records, 29% indicated species co-occurrence. Co-occurrence was not random: occurred more frequently when resource suitability was very high or very low. This result suggests an optimised use of space by termite communities.
Environment enrichment (EE) promotes morphological changes in astrocytes and gliogenesis, as well... more Environment enrichment (EE) promotes morphological changes in astrocytes and gliogenesis, as well an increment in the synapses number of hippocampus. In addition, exposure to EE is known to increase the astrocytic number and volume in cortical regions. The glutamine synthetase (GS) is an astrocyte enzyme that converts glutamate into glutamine, which play an important role in the glutamate/glutamine cycle. Here, we hypothesized that the GS activity would be increased in the cortex and hippocampus of mice living in EE. For this, mice were assigned randomly in two housing conditions: standard condition (SC) or enriched environment (EE) and the GS activity was evaluated after 9 weeks. Our results showed that EE did not promote any significant change in GS activity in both regions tested. Future studies must focus on the temporal analyses of GS activity after EE conditions as well in other species and/or strains and during distinct age of life in order to understand the factors affecting the GS activity after exposition to EE conditions.
Behavioural responses of organisms are frequently affected by variation in resource availability.... more Behavioural responses of organisms are frequently affected by variation in resource availability. For eusocial insects, the nutritional status of the colony can modulate responses to chemical cues determining intra-and inter-colonial aggressiveness. Species co-occurrence in termites seems to be modulated by resource availability. Here, we tested the effects of resource availability on acceptance of chemical cues and aggressive behaviour in the Neotropical termite Nasutitermes aff. coxipoensis (Termitidae: Nasutitermitinae). Nasutitermes aff. coxipoensis nests were transplanted into three plots in which resource availability was manipulated over 4 months. Experiments were carried out to evaluate: (i) colony response to internal chemical cues and those of neighbouring colonies reared under the same resource levels; (ii) the choice among chemical paths of colonies reared at different resource levels; and (iii) inter-colony aggression to nestmates and to neighbouring colonies reared under the same resource levels. Our results suggest that resource availability affects acceptance of chemical cues, path choice and aggression in N. aff. coxipoensis. Resource availability may thus modulate behav-ioural responses influencing coexistence between termite species and other taxa at different spatial scales. Significance statement Environmental resource availability is known to limit a range of traits in animals and plants. Here, we report that resource availability is also responsible for changes in behavioural responses of termites. The behavioural modifications found in the present study contribute to our comprehension of ecological patterns in this important ecological group. This work increases our understanding of mechanisms of co-occurrence and coexistence of termite species, as well as patterns of termite species richness in distinct biomes.
A range of behavioural strategies and sensory abilities allows animals to minimize costs involved... more A range of behavioural strategies and sensory abilities allows animals to minimize costs involved in food search. By building a network of tunnels and presenting a large number of soldiers (i.e., trophically dependent individuals), Nasutitermes spp. termites feature behaviours that imply additional costs during this process. Here we evaluated N. aff. coxipoensis foraging strategies focusing on the role of soldiers during foraging. Field experiments were carried out via nests transplantation to dune areas, and laboratory experiments evaluated termite responses to sternal gland chemical signals from workers and soldiers. N. aff. coxipoensis presented primarily nocturnal foraging. Soldiers typically initiated foraging; however, in established trails, the number of workers was always higher than that of soldiers. The number of trails remained constant over time, while the number of tunnels increased linearly over time. A higher proportion of tunnels originated in surrounding areas than directly from the nests. At observation points with tunnels, there were more stationary than walking soldiers; the opposite was true at observation points without tunnels. In mixed groups, the workers chose to follow soldier chemical signals, and in these groups, soldiers were the first to follow trails. Our results allowed us to identify a not common foraging strategy in termite species; which included the establishment of trails followed by construction of tunnels. Such foraging strategies occur predominantly at night and soldiers play a key role in the foraging process. This foraging strategy reported here seems to be employed to optimize energetic gain.
Rapid Communications in Mass Spectrometry, 2011
PLoS ONE, 2014
Termite nests are often secondarily inhabited by other termite species ( = inquilines) that cohab... more 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).
PLOS ONE, 2016
Structural and functional traits of organisms are known to be related to the size of individuals ... more Structural and functional traits of organisms are known to be related to the size of individuals and to the size of their colonies when they belong to one. Among such traits, propensity to inquilinism in termites is known to relate positively to colony size. Larger termitaria hold larger diversity of facultative inquilines than smaller nests, whereas obligate inquilines seem unable to settle in nests smaller than a threshold volume. Respective underlying mechanisms, however, remain hypothetical. Here we test one of such hypotheses, namely, that nest defence correlates negatively to nest volume in Constrictotermes cyphergaster termites (Termitidae: Nasutitermitinae). As a surrogate to defence, we used 'patrolling rate', i.e., the number of termite individuals attending per unit time an experimentally damaged spot on the outer wall of their termitaria. We found that patrolling rate decayed allometrically with increasing nest size. Conspicuously higher patrolling rates occurred in smaller nests, while conspicuously lower rates occurred in larger nests presenting volumes in the vicinity of the threshold value for the establishment of inquilinism. This could be proven adaptive for the host and guest. At younger nest age, host colonies are smaller and presumably more vulnerable and unstable. Enhanced defence rates may, hence, prevent eventual risks to hosts from inquilinism at the same time that it prevents inquilines to settle in a still unstable nest. Conversely, when colonies grow and maturate enough to stand threats, they would invest in priorities other than active defence, opening an opportunity for inquilines to settle in nests which are more suitable or less risky. Under this two-fold process, cohabitation between host and inquiline could readily stabilize.
Biology Open, 2015
Alarm signalling is of paramount importance to communication in all social insects. In termites, ... more Alarm signalling is of paramount importance to communication in all social insects. In termites, vibroacoustic and chemical alarm signalling are bound to operate synergistically but have never been studied simultaneously in a single species. Here, we inspected the functional significance of both communication channels in Constrictotermes cyphergaster (Termitidae: Nasutitermitinae), confirming the hypothesis that these are not exclusive, but rather complementary processes. In natural situations, the alarm predominantly attracts soldiers, which actively search for the source of a disturbance. Laboratory testing revealed that the frontal gland of soldiers produces a rich mixture of terpenoid compounds including an alarm pheromone. Extensive testing led to identification of the alarm pheromone being composed of abundant monoterpene hydrocarbons (1S)-α-pinene and myrcene, along with a minor component, (E)-β-ocimene. The vibratory alarm signalling consists of vibratory movements evidenced as bursts; a series of beats produced predominantly by soldiers. Exposing termite groups to various mixtures containing the alarm pheromone (crushed soldier heads, frontal gland extracts, mixture of all monoterpenes, and the alarm pheromone mixture made of standards) resulted in significantly higher activity in the tested groups and also increased intensity of the vibratory alarm communication, with the responses clearly dose-dependent. Lower doses of the pheromone provoked higher numbers of vibratory signals compared to higher doses. Higher doses induced long-term running of all termites without stops necessary to perform vibratory behaviour. Surprisingly, even crushed worker heads led to low (but significant) increases in the alarm responses, suggesting that other unknown compound in the worker's head is perceived and answered by termites. Our results demonstrate the existence of different alarm levels in termites, with lower levels being communicated through vibratory signals, and higher levels causing general alarm or retreat being communicated through the alarm pheromone.
Rapid Communications in Mass Spectrometry, 2011
How do termite inquilines manage to cohabit termitaria along with the termite builder species? Wi... more 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.
PLoS One 9 (1): e85315. doi:10.1371/journal.pone.0085315, Jan 21, 2014
Termite nests are often secondarily inhabited by other termite species ( = inquilines) that cohab... more 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).
Termite nests are often secondarily inhabited by other termite species ( = inquilines) that cohab... more 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).
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Papers by Paulo Cristaldo