Gut content analysis and a new feeding group classification of termites

Abstract

1. Gut content analysis of termites was undertaken using microscopical techniques. The 46 study species covered the entire range of taxonomic and feeding forms within the Order.2. Inter-speci®c gut contents data were analysed using principal components analysis, placing species along a clear humi®cation gradient based on variations in the amount of silica and plant tissue fragments in the gut.3. Redundancy analysis was used to ®nd morphological correlates of the observed variation in gut contents. A total of 22 morphological characters (out of 45 candidate characters) were correlated signi®cantly with the gut contents.4. Three of the 22 signi®cantly correlated characters unambiguously de®ned feeding groups, which were designated groups I to IV in increasing order of humi®cation of the feeding substrate. Group I contains lower termite dead wood and grass-feeders; group II contains Termitidae with a range of feeding habits including dead wood, grass, leaf litter, and micro-epiphytes; group III contains Termitidae feeding in the organic rich upper layers of the soil; group IV contains the true soil-feeders (again all Termitidae), ingesting apparently mineral soil. These groupings were generally supported statistically in a canonical covariance analysis, although group II apparently represents termite species with a rather wide range of feeding habits.5. Using existing hypotheses of termite phylogenetic relationships, it seems probable that group I feeders are phylogenetically basal, and that the other groupings have arisen independently on a number of occasions. Soil-feeding (i.e. group III and group IV feeding) may have evolved due to the co-option of faecal material as a fungal substrate by Macrotermitinae-like ancestral forms. As a consequence, these forms would have been constrained to build nest structures from soil and would therefore have passed at least some soil through their guts.

Functional structure of ant and termite assemblages in old growth forest, logged forest and oil palm plantation in Malaysian Borneo

“…Ant and termite reproductives were excluded from counts to avoid including vagrants, and immature termites could not be identified. Ants and termites show niche conservatism within genera (Andersen 2000;Donovan et al 2001) and so genus-level identification of both taxa was suitable for functional group assignment. Number of encounters of each ant and termite genus within a quadrat, defined as the sum of the number of pits and number of examinations of dead wood ('hits') containing that genus, was used as a surrogate measure of occurrence (referred to henceforth simply as ''occurrence'') (following Davies et al 2003).…”

“…Ants were assigned to functional groups following Andersen (2000) and Brown (2000) and termites to feeding groups following Donovan et al (2001) (Table 1). Ants were grouped according to differences in behaviour, dominance and temperature preferences in addition to feeding strategy, whereas termite groups were based only on feeding differences (position along the humification gradient) and associated morphological (mandibular and gut structural) characters (Donovan et al 2001).…”

“…Ants were grouped according to differences in behaviour, dominance and temperature preferences in addition to feeding strategy, whereas termite groups were based only on feeding differences (position along the humification gradient) and associated morphological (mandibular and gut structural) characters (Donovan et al 2001). Differences in these ant and termite functional groups between treatments are therefore likely to be associated with differences in the rate of decomposition, the type of material being decomposed (by termites) and the extent and type of predation (by ants).…”

“…dead wood, leaf litter and soil). They play major roles in processes such as decomposition, and nutrient and carbon cycling (Eggleton et al 1997;Jones and Eggleton 2000;Donovan et al 2001). Ants disperse seeds, assist soil processing and nutrient cycling, and are mutualists with a range of species (e.g.…”

Insect‐mediated nitrogen dynamics in decomposing wood

“…Members of the more basal families (non-termitids or 'lower-termites') are predominantly wood-feeders, whereas the termitids ('higher termites') exhibit more diverse feeding habits (e.g. grass, soil, cultivated fungi), including many species that never feed on wood (Donovan et al, 2001). One important distinction between these two groups is that the guts of non-termitids (as in wood-feeding Cryptocercus cockroaches) contain symbiotic protists that play an important role in lignocellulose digestion and other functions (Brune & Ohkuma, 2011;Brune, 2014).…”