Phylogenetic relationship among cockroach families inferred from mitochondrial12S rRNA gene sequence

A number of phylogenies exist for cockroaches that differ in the postulated relationships among families and genera. The relationship of the wood-feeding genus, Cryptocercus, to other cockroach families and to termites, has generated considerable debate. Grandcolas (1994), based on morphological analysis, synonymized the family Cryptocercidae with Polyphagidae and placed the genus Cryptocercus in the subfamily Polyphaginae. To determine if an independent set of characters supports the placement of Cryptocercus in Polyphaginae, a phylogenetic analysis of relationships among representative genera of the five cockroach families was undertaken. DNA sequence of a -430 base pair portion of the mitochondrial small ribosomal subunit gene from representatives of Blattidae, Blattellidae, Blaberidae and Cryptocercus, previously published by Kambhampati (1995) and Kambhampati et al. (1996), and the homologous sequence from representatives of Polyphagidae were used in the analysis. A total of twenty cockroach taxa and three termite genera were included in the study. Because a recent study showed that Cryptocercus punctulatus consists of a species complex, DNA sequence from four individuals collected in different parts of the U.S.A. was included in the study. The trees estimated from parsimony and neighbour-joining analyses indicated that Cryptocercus is a monophyletic clade which is most closely related to members of Blattidae. Polyphagidae is indicated as a sister group to the Blattidae + Cryptocercus complex, suggesting that Polyphagidae may belong to the superfamily Blattoidea rather than to Blaberoidea as proposed by McKittrick (1964). Blaberidae and Blattellidae were sister groups as previously proposed. Based on the present analysis, I propose that the genus Cryptocercus be retained in the family Cryptocercidae. Cockroaches     

A proteomic approach for studying insect phylogeny: CAPA peptides of ancient insect taxa (Dictyoptera, Blattoptera) as a test case

Background  

Neuropeptide ligands have to fit exactly into their respective receptors and thus the evolution of the coding regions of their genes is constrained and may be strongly conserved. As such, they may be suitable for the reconstruction of phylogenetic relationships within higher taxa. CAPA peptides of major lineages of cockroaches (Blaberidae, Blattellidae, Blattidae, Polyphagidae, Cryptocercidae) and of the termite Mastotermes darwiniensis were chosen to test the above hypothesis. The phylogenetic relationships within various groups of the taxon Dictyoptera (praying mantids, termites and cockroaches) are still highly disputed.     

Phylogeny of cockroaches (Insecta,Dictyoptera, Blattodea), with placement of aberrant taxa and exploration of out‐group sampling

We addressed the phylogeny of cockroaches using DNA sequence data from a broad taxon sample of Dictyoptera and other non‐endopterygotan insect orders. We paid special attention to several taxa in which relationships are controversial, or where no molecular evidence has been used previously: Nocticolidae, a family of small, often cave‐dwelling cockroaches, has been suggested to be the sister group of the predaceous Mantodea or of the cockroach family Polyphagidae; Lamproblatta, traditionally placed in Blattidae, has recently been given family status and placed as sister to Polyphagidae; and Saltoblattella montistabularis Bohn, Picker, Klass & Colville, a jumping cockroach, which has not yet been included in any phylogenetic studies. We used mitochondrial (COI + COII and 16S) and nuclear (18S and 28S) genes, and analysed the data using Bayesian inference (BI) and maximum likelihood (ML). Nocticolidae was recovered as sister to Polyphagidae. Lamproblatta was recovered as sister to Blattidae, consistent with the traditional placement (not based on phylogenetic analysis). However, because of the limited support for this relationship and conflict with earlier morphology‐based phylogenetic hypotheses, we retain Lamproblattidae. S. montistabularis was consistently placed as sister to Ectobius sylvestris Poda (Blaberoidea: Ectobinae), indicating that the saltatorial hindlegs of this genus are a relatively recent adaptation. Isoptera was placed within Blattodea as sister to Cryptocercidae. Nocticolidae + Polyphagidae was sister to Isoptera + Cryptocercidae, and Blaberoidea was sister to the remaining Blattodea.     

Inclusion of rare taxa from Blattidae and Anaplectidae improves phylogenetic resolution in the cockroach superfamily Blattoidea

Cockroaches are an ecologically and economically important insect group, but some fundamental aspects of their evolutionary history remain unresolved. In particular, there are outstanding questions about some of the deeper relationships among cockroach families. As a group transferred from Blaberoidea Saussure to Blattoidea Latreille, the evolutionary history of the family Anaplectidae Walker requires re-evaluation. In our study, we infer the phylogeny of Blattoidea based on the mitochondrial genomes of 28 outgroup taxa and 67 ingroup taxa, including 25 newly sequenced blattoid species mainly from the families Anaplectidae and Blattidae Latreille. Our results indicate that Blattoidea is the sister group of the remaining Blattodea Brunner von Wattenwyl and that Blattoidea can be divided into three main clades: Blattidae + Tryonicidae McKittrick & Mackerras, Lamproblattidae McKittrick + Anaplectidae and Termitoidae Latreille + Cryptocercidae Handlirsch. Our analyses provide robust support for previously uncertain hypotheses. The sister group of Termitoidae + Cryptocercidae (Xylophagodea Engel) is inferred to constitute the rest of Blattoidea, for the first time. Within Blattidae, Hebardina Bey-Bienko is placed as the sister lineage to the rest of Blattidae. The subfamily Archiblattinae is polyphyletic, Blattinae is paraphyletic and Polyzosteriinae is monophyletic (Macrocercinae Roth not included); the genus Periplaneta Burmrister is polyphyletic. Based on the results of our phylogenetic analyses, we have revised these taxa. A new subfamily, Hebardininae subfam.nov. , is proposed in Blattidae. Archiblattinae and Shelfordella Adelung are synonymized with Blattinae and Periplaneta, respectively: Archiblattinae Kirby syn.nov. and Shelfordella Adelung syn.nov. Our inferred divergence times indicate that Blattoidea emerged in the Late Triassic, with six families in Blattoidea diverging in the Middle and Late Jurassic. We suggest that the divergences among lineages of Asian Blattidae and Anaplectidae were driven by the uplift of the Himalayas and deglaciation during the Quaternary, leading to the present-day distributions of these taxa.     

Proteinase, amylase, and proteinase-inhibitor activities in the gut of six cockroach species

Representative species, two from each of the cockroach families Blattidae, Blattellidae, and Blaberidae, have similar morphology of the digestive tract but differ in the physiology of digestion. The pH of crop and along the midgut varies in different species from 5.9 to 9.0 and the redox parameter from 10.1 to 12.9. Activities of proteinases and amylases in comparable gut regions differ among the species up to 100 times. Proteolytic activity is high in the midgut and moderate in the crop of Blattidae; in the other species, it is very low in the crop and increases to a moderate level in the posterior half of midgut (PM). The level of amylolytic activity is similar in the examined gut compartments of Blattidae and Blattellidae but low in the PM of Blaberidae. Blaberidae are also characterized by a high potential of the salivary glands, crop, and midgut to inhibit subtilisin, trypsin, and chymotrypsin. Inhibition of these proteinases by the extracts of salivary glands and gut is several orders of magnitude lower and often undetectable in the representatives of Blattidae and Blattellidae.     

Complete mitochondrial genome of Periplaneta brunnea (Blattodea: Blattidae) and phylogenetic analyses within Blattodea

The complete mitochondrial genome (mitogenome) of Periplaneta brunnea was sequenced in this study and used to reconstruct the phylogenetic relationship of Blattodea. The circular mitogenome was 15,604?bp long and exhibited typical gene organization and order, consistent with other sequenced Periplaneta mitogenomes. The initiation codon of the P. brunnea COX1 gene was unusual in that no typical ATN or TTG start codon was found. The two longest intergenic spacer sequences found in the P. brunnea mitogenome were 21 and 17?bp long. Twenty-one base spacer had a 4?bp motif (TATT) between tRNA-Glu and tRNA-Met that conservatively displayed in 9 sequenced blattarian mitogenomes. The second spacer was between tRNA-Ser (UCN) and NAD1 containing a 7?bp motif (WACTTAA) that was highly conserved in 14 blattarian mitogenomes. The control region showed a relatively fixed motif present in 6 Blattidae mitogenomes, with a big stem-loop structure. Phylogenetic analyses were conducted using site-homogeneous models based on 13 protein-coding genes (PCGs) and two RNA genes. The trees derived from Bayesian inference and maximum likelihood analyses and recovered a relatively stable relationship among major lineages except for the position of Polyphagidae and inter-family relationships of Blaberidae. Analyses supported the monophyly of Blattidae, Blaberidae, Blattellidae, Polyphagidae, Dictyoptera, and the paraphyly of Blattaria. We also found Mantodea was the sister clade to (Blattaria?+?Isoptera), being the basal position of Dictyoptera in all topologies. Meanwhile, our results also consistently supported that Isoptera should be clustered with Blattaria of Blattodea.     

Testing decreasing variabililty of cockroach forewings through time using four Recent species: Blattella germanica,Polyphaga aegyptiaca,Shelfordella lateralis and Blaberus craniifer,with implications for the study of fossil cockroach forewings

Abstract Vr?anský (2000) considered there is decreasing variability in the forewings of cockroaches through time, based on a study of fossil and Recent species. This study tests his theory, based on a study of four Recent species of cockroaches: Blattella germanica (Blattellidae), Polyphaga aegyptiaca (Polyphagidae), Shelfordella lateralis (Blattidae) and Blaberus craniifer (Blaberidae). The new results, based on the coefficient of variation (CV) of the number of veins, indicate that Recent species can be more variable than fossil species and therefore do not support the theory. The results also show that at least 30 complete wings of the same species are required for a reliable CV value that is comparable between species.     

Primary structures of hypertrehalosaemic neuropeptides isolated from the corpora cardiaca of the cockroaches Leucophaea maderae, Gromphadorhina portentosa, Blattella germanica and Blatta orientalis and of the stick insect Extatosoma tiaratum assigned by tandem fast atom bombardment mass spectrometry

Hypertrehalosaemic peptides were isolated by reversed-phase high-performance liquid chromatography from corpora cardiaca of four species of cockroaches (Leucophaea maderae, Gromphadorhina portentosa, Blattella germanica, and Blatta orientalis) and one stick insect species (Extatosoma tiaratum), and their primary sequences were assigned by collision-induced decomposition tandem fast atom bombardment mass spectrometry (FABMS/CID/MS). The members of the cockroach families Blaberidae (L. maderae and G. portentosa) and Blattellidae (B. germanica) contained an identical decapeptide (Glu-Val-Asn-Phe-Ser-Pro-Gly-Trp-Gly-ThrNH2), whereas the member of the cockroach family Blattidae (B. orientalis) had two octapeptides (Glu-Val-Asn-Phe-Ser-Pro-Asn-TrpNH2 and Glu-Leu-Thr-Phe-Thr-Pro-Asn-TrpNH2). The structure of the stick insect hypertrehalosaemic compound was assigned as a decapeptide (Glu-Leu-Thr-Phe-Thr-Pro-Asn-Trp-Gly-ThrNH2). The respective synthetic peptides elevated blood carbohydrates in their respective acceptor species. The results are discussed in the light of family-specificity of members of the adipokinetic hormone/red pigment-concentrating hormone family.     

A mitochondrial genome phylogeny of termites (Blattodea: Termitoidae): Robust support for interfamilial relationships and molecular synapomorphies define major clades

Despite their ecological significance as decomposers and their evolutionary significance as the most speciose eusocial insect group outside the Hymenoptera, termite (Blattodea: Termitoidae or Isoptera) evolutionary relationships have yet to be well resolved. Previous morphological and molecular analyses strongly conflict at the family level and are marked by poor support for backbone nodes. A mitochondrial (mt) genome phylogeny of termites was produced to test relationships between the recognised termite families, improve nodal support and test the phylogenetic utility of rare genomic changes found in the termite mt genome. Complete mt genomes were sequenced for 7 of the 9 extant termite families with additional representatives of each of the two most speciose families Rhinotermitidae (3 of 7 subfamilies) and Termitidae (3 of 8 subfamilies). The mt genome of the well supported sister-group of termites, the subsocial cockroach Cryptocercus, was also sequenced. A highly supported tree of termite relationships was produced by all analytical methods and data treatment approaches, however the relationship of the termites+Cryptocercus clade to other cockroach lineages was highly affected by the strong nucleotide compositional bias found in termites relative to other dictyopterans. The phylogeny supports previously proposed suprafamilial termite lineages, the Euisoptera and Neoisoptera, a later derived Kalotermitidae as sister group of the Neoisoptera and a monophyletic clade of dampwood (Stolotermitidae, Archotermopsidae) and harvester termites (Hodotermitidae). In contrast to previous termite phylogenetic studies, nodal supports were very high for family-level relationships within termites. Two rare genomic changes in the mt genome control region were found to be molecular synapomorphies for major clades. An elongated stem-loop structure defined the clade Polyphagidae + (Cryptocercus+termites), and a further series of compensatory base changes in this stem-loop is synapomorphic for the Neoisoptera. The complicated repeat structures first identified in Reticulitermes, composed of short (A-type) and long (B-type repeats) defines the clade Heterotermitinae+Termitidae, while the secondary loss of A-type repeats is synapomorphic for the non-macrotermitine Termitidae.     

Foregut microspines in four families of cockroaches (Blattaria)

The microspines of the cockroach foregut were investigated in order to determine their fine structure, variation, patterns of distribution, and possible functions. The following were studied: Blaberidae (4 species), Blatellidae (3 species), Blattidae (2 species), and Cryptocercidae (one species). Elongate microspines (over 30 μm), usually several attached to a basal plate, were found in the buccal cavity and anterior and posterior pharynx of blaberids and blattids, whereas moderate (15–20 μm) to short (1–5 μm) microospines were found in 2 regions in the blattellid and cryptocercid cockroaches. Short microspines (1–5 gmm) individually attached to a basal plate occurred in the esophagus, crop, proventriculus and stomodeal valve regions in all families studied. Microspines appear to be useful in understanding systematics and evolution of cockroaches. The possible role of elongate microspines in retaining food particles during regurgitation behavior is postulated.     

Phylogeny and Biogeography of Wood-Feeding Cockroaches, Genus Salganea Stål (Blaberidae: Panesthiinae), in Southeast Asia Based on Mitochondrial DNA Sequences

Molecular phylogenetic relationships among 25 species of the wood-feeding cockroach belonging to the genus Salganea St?l (Panesthiinae; Blaberidae) in Southeast Asia were analyzed based on the DNA sequence of the complete mitochondrial cytochrome oxidase II (COII) gene. Most basal relationships among species of Salganea are poorly resolved by both neighbor-joining and nonweighted parsimony analyses, suggesting the possibility of a hard polytomy due to a rapid and potentially simultaneous radiation early in the history of the genus. For more apical relationships, however, some interesting phylogenetic relationships were recognized. The monophyly of the two species groups, morio and foveolata, the former of which is distributed mainly in the Sunda lands (containing the Malay Peninsula, Sumatra, Java, and Borneo), whereas the latter is Sulawesi endemic, was strongly supported. Based on the inferred phylogenetic patterns and recent palaeogeographic scenario for Southeast Asia, it is suggested that a radiation of Salganea species occurred in Southeast Asia presumably in the early Tertiary, and several barriers against dispersal and gene flow, such as the formation of straits or high mountains, have arisen from the middle Tertiary. Received: 4 April 2001 / Accepted: 20 April 2001     

Phylogeny of Anophelinae (Diptera: Culicidae) based on nuclear ribosomal and mitochondrial DNA sequences

Abstract Phylogenetic relationships among thirty-two species of mosquitoes in subfamily Anophelinae are inferred from portions of the mitochondrial genes COI and COII, the nuclear 18S small subunit rRNA gene and the expansion D2 region of the nuclear large subunit 28S rRNA gene. Sequences were obtained from the genera Anopheles , Bironella and Chagasia . Representatives of all six subgenera of Anopheles were included: Anopheles , Cellia , Kerteszia , Lophopodomyia , Nyssorhynchus and Stethomyia. Using parsimony and maximum likelihood methods, various combinations of these DNA sequence data were analysed separately: 18S, 28S, combined 18S and 28S, combined COI and COII, and combined 18S, 28S, COI and COII ('total evidence'). The combined rDNA data contain strong phylogenetic signal, moderately to strongly supporting most clades in MP and ML analyses; however, the mtDNA data (analysed as either nucleotide or amino acid sequences) contain little phylogenetic signal, except for relationships of very recently derived groups of species and, at the deepest level, for the monophyly of Anophelinae. The paraphyly of Anopheles relative to Bironella is confirmed by most analyses and statistical tests. Support for the monophyly of subgenera Anopheles , Cellia , Kerteszia and Nyssorhynchus is indicated by most analyses. Subgenus Lophopodomyia is reconstructed as the sister to Bironella , nested within a clade also containing Nyssorhynchus and Kerteszia . The most basal relationships within genus Anopheles are not well resolved by any of the data partitions, although the results of statistical analyses of the rDNA data (S-H-tests, likelihood ratio tests for monophyly and Bayesian MCMC analyses) suggest that the clade consisting of Bironella , Lophopodomyia , Nyssorhynchus and Kerteszia is the sister to the clade containing Cellia and Anopheles .     

利用叶绿体基因组数据解析锦葵科梧桐亚科的系统位置和属间关系

分子系统学研究将传统梧桐科与锦葵科、木棉科和椴树科合并为广义锦葵科,并进一步分为9个亚科.然而,9个亚科之间的关系尚未完全明确,且梧桐亚科内的属间关系也未得到解决.为了明确梧桐亚科在锦葵科中的系统发育位置,厘清梧桐亚科内部属间系统发育关系,该研究对锦葵科8个亚科进行取样,共选取55个样本,基于叶绿体基因组数据,采用最大...     

Social biology of the wood-feeding cockroach genus <Emphasis Type="Italic">Salganea</Emphasis> (Dictyoptera,Blaberidae, Panesthiinae): did ovoviviparity prevent the evolution of eusociality in the lineage?

Recent phylogenetic studies indicating that termites are eusocial cockroaches closely related to the genus Cryptocercus have generated fresh interest in wood-feeding Blattaria. Here we summarize the social biology of the wood-feeding genus Salganea (Blaberidae: Panesthiinae). As in Cryptocercus, Salganea exhibits long term, biparental care that includes the defense and feeding of young nymphs. Unlike Cryptocercus, however, Salganea is iteroparous: most studied species reproduce periodically over their lifetime. These divergent reproductive strategies are likely related to parental costs associated with their differing reproductive modes: Cryptocercus is oviparous, while Salganea is ovoviviparous. The pattern of parental investment associated with ovoviviparous reproduction may be one reason why Salganea and other ovoviviparous wood-feeding cockroach lineages did not evolve eusociality. Received 21 August 2007; revised 25 January 2008; accepted 22 Feburary 2008.     

Relationships among the major lineages of Dictyoptera: the effect of outgroup selection on dictyopteran tree topology

Abstract Dictyoptera, comprising Blattaria, Isoptera, and Mantodea, are diverse in appearance and life history, and are strongly supported as monophyletic. We downloaded COII, 16S, 18S, and 28S sequences of 39 dictyopteran species from GenBank. Ribosomal RNA sequences were aligned manually with reference to secondary structure. We included morphological data (maximum of 175 characters) for 12 of these taxa and for an additional 15 dictyopteran taxa (for which we had only morphological data). We had two datasets, a 59‐taxon dataset with five outgroup taxa, from Phasmatodea (2 taxa), Mantophasmatodea (1 taxon), Embioptera (1 taxon), and Grylloblattodea (1 taxon), and a 62‐taxon dataset with three additional outgroup taxa from Plecoptera (1 taxon), Dermaptera (1 taxon) and Orthoptera (1 taxon). We analysed the combined molecular?morphological dataset using the doublet and MK models in Mr Bayes , and using a parsimony heuristic search in paup . Within the monophyletic Mantodea, Mantoida is recovered as sister to the rest of Mantodea, followed by Chaeteessa; the monophyly of most of the more derived families as defined currently is not supported. We recovered novel phylogenetic hypotheses about the taxa within Blattodea (following Hennig, containing Isoptera). Unique to our study, one Bayesian analysis places Polyphagoidea as sister to all other Dictyoptera; other analyses and/or the addition of certain orthopteran sequences, however, place Polyphagoidea more deeply within Dictyoptera. Isoptera falls within the cockroaches, sister to the genus Cryptocercus. Separate parsimony analyses of independent gene fragments suggest that gene selection is an important factor in tree reconstruction. When we varied the ingroup taxa and/or outgroup taxa, the internal dictyopteran relationships differed in the position of several taxa of interest, including Cryptocercus, Polyphaga, Periplaneta and Supella. This provides further evidence that the choice of both outgroup and ingroup taxa greatly affects tree topology.     

Plastid phylogenomics and molecular evolution of Alismatales

Past phylogenetic studies of the monocot order Alismatales left several higher‐order relationships unresolved. We addressed these uncertainties using a nearly complete genus‐level sampling of whole plastid genomes (gene sets representing 83 protein‐coding and ribosomal genes) from members of the core alismatid families, Tofieldiaceae and additional taxa (Araceae and other angiosperms). Parsimony and likelihood analyses inferred generally highly congruent phylogenetic relationships within the order, and several alternative likelihood partitioning schemes had little impact on patterns of clade support. All families with multiple genera were resolved as monophyletic, and we inferred strong bootstrap support for most inter‐ and intrafamilial relationships. The precise placement of Tofieldiaceae in the order was not well supported. Although most analyses inferred Tofieldiaceae to be the sister‐group of the rest of the order, one likelihood analysis indicated a contrasting Araceae‐sister arrangement. Acorus (Acorales) was not supported as a member of the order. We also investigated the molecular evolution of plastid NADH dehydrogenase, a large enzymatic complex that may play a role in photooxidative stress responses. Ancestral‐state reconstructions support four convergent losses of a functional NADH dehydrogenase complex in Alismatales, including a single loss in Tofieldiaceae.     

Interspecific morphological variation in the wood-feeding cockroach, Cryptocercus (Dictyoptera: Cryptocercidae)

Appalachian species of Cryptocercus (Dictyoptera: Cryptocercidae) display considerable genetic variation, but little morphological variation has been reported. We employed light and scanning electron microscopy to investigate variation in male and female reproductive structures among four species of Cryptocercus. Our results indicated consistent, species-specific differences exist in the genitalia of the four species. Males exhibit moderate interspecific differences in the shape of the subgenital plate and third left phallomere hook. Females display consistent interspecific differences in the size of setae on the basivalvula and great differences in size, number, and pattern of setae on the base of the second valves. Together, the interspecific variation in female reproductive structures can be used to identify each of the four Cryptocercus species that occur in the Appalachian Mountains.     

On the Social Organisation,Alarm and Fighting in the Primitive Cockroach Cryptocercus punctulatus Scudder

The wood-feeding cockroach Cryptocercus is usually believed to live in aggregations. Field observations, however, gave evidence for the existence of distinct family groups living in different gallery systems. This study investigates intraspecific behavioural interactions with respect to the social structure. The interactions among family members were observed in artificial burrows in the laboratory. Individuals from different families were brought together experimentally and the resulting alarm and fighting behaviour was studied. The importance of Cryptocercus for the evolution of termite sociality is discussed.     

Phylogenetic analyses of fat body endosymbionts reveal differences in invasion times of blaberid wood-feeding cockroaches (Blaberidae: Panesthiinae) into the Japanese archipelago

Cockroaches have endosymbiotic bacteria in their fat bodies. Recent molecular phylogenetic analyses on both hosts and endosymbionts have revealed that co-evolution has occurred throughout the history of cockroaches and termites. Co-cladogenesis was also shown among closely related taxa (woodroach genus Cryptocercus; Cryptocercidae), and thus endosymbiont data are likely to be useful for biogeographical analyses. To test the possibility of co-cladogenesis among inter-and intraspecific taxa, as well as the utility of endosymbiont data for inferring biogeographical scenarios, we analyzed rRNA genes of endosymbionts of Japanese and Taiwanese Panesthiinae (Salganea and Panesthia; Blaberidae), on which phylogenetic analyses previously had been performed based on the mitochondrial genes. Statistical analyses on the topologies inferred from both endosymbiont and host mitochondria genes showed that co-cladogenesis has occurred. The endosymbiont sequences examined appear to have evolved in a clock-like manner, and their rate of evolution based on the host fossil data showed a major difference in the time of invasion of the two Japanese genera, that is congruent with the recent analyses of their mitochondrial genes.     

Origin of termite eusociality: trophallaxis integrates the social,nutritional, and microbial environments

1. Numerous cladistic analyses have converged: termites are a monophyletic clade embedded within the paraphyletic cockroaches, and sister group to the biparental, wood‐feeding cockroach Cryptocercus. The latter is, therefore, an appropriate model for testing assumptions regarding early termite evolution. 2. The ground plan of the termite ancestor is reviewed based on shared characters of ecology, life history, and behaviour in Cryptocercus and incipient termite colonies, and includes two levels of dependence: a reliance of all individuals on gut microbiota, and dependence of early instars on parental care. Both these conditions co‐evolved with parent‐to‐offspring proctodeal trophallaxis. 3. The termite ancestor lived in a single log serving as food and nest. This ‘one‐piece’ nesting ecology prioritises nitrogen conservation and strongly influences interacting social, nutritional, and microbial environments. Each of these environments individually and in combination profoundly affect cockroach development. 4. Proctodeal trophallaxis integrates the social, nutritional, and microbial environments. A change in trophallactic behaviour, from parental to alloparental, can, therefore, shift developmental trajectories, ultimately adding a third level of dependence. The death of gut protists during the host molting period and consequent interdependence of family members shifted the hierarchical level at which selection acted; fixation of eusociality quickly followed. 5. The basic nesting ecology did not change when termites evolved eusociality, the change occurred in the allocation and use of existing resources within the social group, driven by nitrogen scarcity, mediated by trophallaxis, and made possible by a strongly lineage‐specific set of life history characteristics.