Here, we provide evidence for a new aphid species from the genus Rhopalosiphum Koch, based upon an Australian survey of variation in the mitochondrial cytochrome oxidase I gene, and subsequently validated by cytochrome b, nuclear microsatellites, nuclear sequence characterized amplified region locus, and karyotypic analyses. Despite the new species being morphologically very similar to Rhopalosiphum padi (L.), there was significant genetic differentiation, with the new species being closer to the Rhopalosiphum insertum (Walker) group. Karyotypic analyses indicated a putative hybrid origin for the new species, but mitochondrial and nuclear DNA sequence data showed that the available Australian and overseas populations of Rhopalosiphum spp. did not serve as parental lineages. Diagnostic methods were developed that enabled the identification of the new species based on morphometric data and a polymerase chain reaction-restriction fragment length polymorphism based molecular technique.

Collections of parasitoids attacking the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), in South Korea yielded specimens that were originally identified as Binodoxys communis (Gahan) (Hymenoptera: Braconidae). We report here on laboratory studies indicating that this population is actually a previously unknown species of Binodoxys. Four classes of comparisons were made between the Korean population and a Chinese population that also had been identified as B. communis. The comparisons included 1) mating trials coupled with behavioral observations and spermathecal examinations, 2) assessment of nucleotide divergence at two mitochondrial and two nuclear gene loci, 3) patterns of host use, and 4) reassessment of morphological characters. These studies revealed premating reproductive isolation of the two populations and minor nucleotide differences in mitochondrial cytochrome oxidase I sequences and nuclear internal transcriber spacer 1 sequences, providing strong indications that they are different species. Subtle morphological differences also were discovered that confirmed that the Chinese population corresponds to B. communis, whereas the Korean population does not. We propose the name Binodoxys koreanus StarÝ, sp. n. for the Korean population. The two species exhibited similar host ranges in the laboratory, the most notable exception being that B. koreanus, sp. n. is better able to develop in a population of Aphis craccivora Koch that harbors the bacterial endosymbiont Hamiltonella defensa Moran, which seems to strongly interfere with the development of B. communis. We discuss the implications of our results for biological control introductions against the soybean aphid in North America.

Some phorid flies of the genus Pseudacteon Coquillett parasitize workers of Solenopsis geminata (F.) complex fire ants. The group is found to comprise at least 21 species of flies, of which 11 are new to science and described here: P. amuletum, P. andinus, P. annulus, P. catarinae, P. deltoides, P. hippeus, P. kungae, P. laticarinatus, P. palomita, P. quinni, and P. robustus. An identification key to the females is included. This expansion of known Pseudacteon species parasitizing the S. geminata complex makes it an interesting system for comparison with Pseudacteon flies that parasitize fire ants of the S. saevissima (Smith) complex.

One new genus, Pseudomenotelus from México, is proposed within Lygaeoidea (Ozophorini) based on the new species P. oculatus from the state of Chiapas in Mexico. In addition, two new species from Honduras are described in the genus Pseudomenus, P. hondurensis and P. olanchus, each belonging to Ozophorini. A key to the Mexican genera of Ozophorini is included, as well as a key to the known species of Pseudomenus. All taxa here reported are leaf-litter-inhabiting and were collected in mesophilous forest.

Two new fossil species of Kalligrammatidae (Neuroptera) are described from the Middle Jurassic locality at Daohugou, Inner Mongolia, China: Limnogramma hani n. sp. and Limnogramma mongolicum n. sp. Some venational homologies in Neuroptera are discussed briefly.

Wing venation, two-dimensional and with easily recognized reference points at vein junctions, presents an opportunity for the development of automated insect identification. Using a suite of continuous characters, I investigated the use of wing morphometry for computerized insect identification of cryptic species of the aphid genus Mindarus. A priori groups were determined using cytochrome oxidase 1 DNA barcodes. Discriminant function analysis of 24 wing measurements consistently grouped individuals of unknown taxonomic affinity with the correct a priori groups. The results suggest that diagnostic signal is present in wing morphometry, but the signal is considerably stronger with the addition of morphometry from other aphid appendages, namely, 10 leg and antennal segments. Almost all Mindarus collected in eastern North America have been determined as the balsam twig aphid, Mindarus abietinus Koch (Hemiptera: Aphididae), but molecular diagnostics reveals that the Palearctic species is not present in the Western Hemisphere. Schizoneura pinicola Thomas has been considered a North American synonym of M. abietinus. Morphometric discriminant function analysis suggests that the Abies-feeding eastern North American population is M. pinicolus. The species is here reinstated with a new combination and redescribed.

Dendroctonus pseudotsugae Hopkins infests Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, throughout the distribution of that tree species from British Columbia to northern Mexico. The subspecies Dendroctonus pseudotsugae barragani Furniss was described from the mountains of Chihuahua, Sierra Madre Occidental, Mexico, whereas the nominal subspecies, Dendroctonus pseudotsugae pseudotsugae Hopkins, occurs north of Mexico. The description of D. p. barragani was based on the only known Mexican population at that time. More recently, new populations of this beetle have been discovered at 13 additional localities in Chihuahua, Durango, Coahuila, and Nuevo Leon, Mexico. To test whether these additional populations support the existence of two subspecies, we performed a taxonomic reassessment combining molecular markers (cytochrome oxidase I), morphological characters used in the original description, and newly described morphological characters. Phylogenetic analysis of 89 haplotypes confirms that the Mexican populations are distinct from the sampled populations in the United States and Canada. Morphological analysis indicates that intraspecific variation is greater than previously considered within Mexican populations. However, at least seven characters on the head, pronotum, and elytra (including three previously undescribed characters of frons sculpture) consistently discriminate among Canada—U.S. and Mexico populations. The extension of the known distribution of this beetle in Mexico and verification of its subspecific status will aid in the management and conservation of Pseudotsuga in Mexico.

The pollen beetle genus Anthystrix Kirejtshuk, 1981 previously included six South African species characterized by unusual dimorphic development of male antennal characters. The genus is revised and three new species are described from South Africa, including Anthystrix endroedyi new species, Anthystrix flabellicornis new species, and Anthystrix megalocera new species. Anthystrix luculenta Kirejtshuk & Easton 1988, Anthystrix rotundiclava Kirejtshuk & Easton 1988, and Anthystrix martini (Grouvelle, 1899) need to be transferred to two new undescribed genera. These new genera will globally include ≈20 species, most of which remain undescribed or previously attributed to the unrelated genus Meligethinus Grouvelle, 1906. One new synonymy is proposed: Meligethinus uhligi Kirejtshuk & Easton, 1988, = Pria martini Grouvelle, 1899, syn. nov. Larval host plants of Anthystrix species are reported as dioecious Asteraceae trees within the tribe Tarchonantheae (Tarchonanthus). An identification key to all Anthystrix species is provided.

Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) is a quarantine pest of apple (Malus sp.) in Washington state that is almost identical morphologically to Rhagoletis zephyria Snow, a nonpest of apple. Historically, the longer ovipositor in R. pomonella has been used to separate it from R. zephyria, despite overlap in ovipositor lengths. Here, the objectives were to determine whether use of multiple body measurements and wing shape can improve discrimination of the species. Ovipositor lengths allowed 94.6% correct identification of female R. pomonella but only 7.0% correct identification of R. zephyria. We found that multiple body measurements and wing shape can better separate these species. Canonical variates analysis (CVA) of nine body measurements in female flies largely separated the species. In contrast, CVA of nine body measurements poorly separated the males of these species. Discriminant analysis using nine body measurements classified female R. pomonella and R. zephyria with 95.4 and 100% accuracy, respectively. Geometric morphometrics and CVA separated wing shapes between species in both sexes. Bookstein shape coordinates indicated that the wing of R. pomonella is more tapered at the tip than that of R. zephyria. Use of wing shape in an assignments test identified female R. pomonella with 98.5% and female R. zephyria with 99.0% accuracy, and it correctly identified 100% of flies whose identities were questionable based on ovipositor lengths. Results indicate that use of multiple body measurements or wing shape is an improvement over the use of ovipositor length alone for identifying female R. pomonella and R. zephyria in Washington state.

In total, 289 termite samples were collected from 45 counties in Indiana during 2002– 2004. Approximately 89% of the collection sites were associated with artificial structures, and almost half of the samples were from inside homes. The rest of the samples were from forested areas. Termite samples were identified based on their morphological characteristics, molecular characteristics, or both. Five species from the genus Reticulitermes were identified, and the relative abundance (percentage of the total collections) of these five species was Reticulitermes flavipes (Kollar) (90.0), Reticulitermes virginicus (Banks) (7.6), Reticulitermes arenincola (Goellner) (1.0), Reticulitermes tibialis (Banks) (1.0), and Reticulitermes hageni Banks (0.3). Based on the distribution map, R. fiavipes was the dominant and the most widely distributed species in Indiana (44 counties); followed by R. virginicus (13 counties). The three other Reticulitermes species, R. arenincola, R. tibialis, and R. hageni, were encountered in only five counties. R. arenincola is considered a rare species and its distribution has been limited to sand dunes near Lake Michigan. However, in this study, two of the three R. arenincola samples were collected outside of its type location. R. tibialis was found in three counties, whereas R. hageni was only found in Evansville, IN. To complement the morphological identifications, a 389-bp region of the mitochondrial DNA (mtDNA) 16S rRNA gene was amplified and sequenced from all five Reticulitermes species. Based on species-specific polymorphisms exhibited in mtDNA sequences, a polymerase chain reaction-restriction fragment length polymorphism—based diagnostic tool was developed to identify samples lacking of diagnostic morphological characters.

The history of the genus Onychiurus is discussed. Four new Onychiurus species are described from North American caves: steinmanni and nathanieli from Colorado, reluctoides from Indiana, and furcisetosus from Virginia. Onychiurus reluctus Christiansen, 1961 is redescribed. A key for all of the known North American species is provided.

Species of Cardinium are intracellular endosymbionts of arthropods. They are known to interfere with the mode of reproduction in some parasitoid wasp and mite hosts, and they are associated with parthenogenesis in the oleander scale, Aspidiotus nerii Bouché (Hemiptera: Diaspididae). Here, we survey A. nerii more broadly for presence of Cardinium species. In total, we tested 593 individuals in 301 populations, representing 132 identified species of armored scale insects, by using polymerase chain reaction (PCR) and sequencing of 16S rDNA. We obtained positive PCR results in 67 individuals of 34 populations, representing 20 species and one unidentified individual. Sequencing of these PCR products yields 20 new Cardinium haplotypes, raising the number of known insect-associated Cardinium haplotypes from 15 to 35. The new host-list elucidates the ecology of Cardinium, which in insects seems to be specialized on plant-feeding Hemiptera and associated parasitoid Hymenoptera. A phylogenetic analysis of all known insect-associated Cardinium 16S sequences reveals deep diversity in armored scale insects and implies horizontal transfer of Cardinium among armored scale insects and their parasitoids.

Eutarsopolipus teteri n. sp. (Acari: Podapolipidae) is described from Platynus teter Chaudoir (Coleoptera: Carabidae) from Chiapas, Mexico, and compared with Eutarsopolipus pterostichi Regenfuss, 1968; E. vernalis Regenfuss, 1968; E. inermis Regenfuss 1974; E. diunculosus Eidelberg 1994; E. fischeri Husband 1998; and E. shpeleyi Husband 2007 in the pterostichi group of Eutarsopolipus. This is the first record of the pterostichi group in Central America. Keys to adult females of 14 groups of the genus Eutarsopolipus and seven species in the pterostichi group are presented.

The life history of Corimelaena incognita (McAtee & Malloch) (Hemiptera: Heteroptera: Thyreocoridae) was studied in southern New Mexico from August 2005 through November 2007, and the immature stages were described. The bug also was reared from egg to adult under controlled laboratory conditions. Adults of this bivoltine species overwintered in leaf litter, emerged in early February, and began feeding on dried fruits of Leucophyllum frutescens (Berlandier) from the previous year, the only host plant observed for this bug; they and their offspring, collectively, fed on the current year's fruit throughout the season until early December. Eggs were found from early April through late September and laid singly, usually glued beneath the bracts of developing fruits. Nymphs were found from late April through late November. This species was reared in the laboratory on fruits of L. frutescens at 25 ± 0.01°C under a photoperiod of 14:10 (L:D) h. The incubation period averaged 8.33 d. The five stadia averaged 7.27, 4.10, 4.51, 4.90, and 8.54 d, respectively. Instars can be distinguished by differences in morphological features including, among others, body size and punctation.

Analyses of mitochondrial DNA sequences (12S, 16S, and COII) were conducted to determine the phylogenetic relationships among the following 11 putative subterranean termites of Coptotermes: Coptotermes cochlearus Xia & He, Coptotermes curvignathus Holmgren, Coptotermes dimorphus Xia & He, Coptotermes formosanus Shiraki, Coptotermes gestroi (Wasmann), Coptotermes kalshoveni Kemner, Coptotermes sepangensis Krishna, and Coptotermes travians (Haviland) from East Asia, and Coptotermes acinaciformis Froggatt, Coptotermes frenchi Hill, and Coptotermes lacteus (Froggatt) from Australia. Available sequences for these species and those of Coptotermes guangzhouensis Ping from GenBank also were included in the analyses. Maximum parsimony and maximum likelihood of the combined nucleotide matrices of the 12S, 16S, and COII genes resulted in two major clades with six subclades: I (C. acinaciformis), II(C. lacteus and C. frenchi), III (C. curvignathus), IV (C. kalshoveni, C. sepangensis and C. travians), V (C. gestroi) and VI (C. formosanus, C. cochlearus, C. dimorphus and C. guangzhouensis). C. cochlearus and C. dimorphus are possibly junior synonyms of C. formosanus with nucleotide differences of up to 1.0%.

The developmental stages and castes of two sympatric subterranean termites, Macro-termes gilvus (Hagen) and Macrotermes carbonarius (Hagen) (Blattodea: Termitidae) were studied and biometric descriptors of each caste were developed for the identification of both species. Biometric descriptors revealed five well-defined groups of larval castes. After sex determination, three larval instars were detected in the development of minor and major worker castes. The first larval instars consist of both males and females which are homogenous in size. Size sexual dimorphism, in which females are smaller than males, occurs in the second larval instars, third larval instars, and worker castes. Minor and major soldiers are female sterile castes. Pictorial evidence of the fourth larval instar of M. carbonarius is presented herein; the individuals closely resemble minor workers but are poorly pigmented and have a distended abdomen, future presoldier-like mandibles, and a meso- and metanotum. In reproductive caste development, nymphs (derived from the first larval instars) undergo five moults from first to fifth instars before becoming winged termites.

Appendage regeneration is a unique tool to study resource allocation trade-offs; the resources allocated to grow an appendage a second time can come at the expense of other structures. We studied the effects of both front and hind leg regeneration on a suite of traits in Anisomorpha buprestoides (Stoll) (Phasmatodea: Pseudophasmatidae), the twostriped walkingstick. This species is ideal for resource allocation questions because it has a relatively long life history as well as a large group of traits to measure for any potential trade-offs (including large defensive glands in the thorax that are used to deter predators). For females, there were no apparent trade-offs with respect to antennae, eyes, defensive glands, nonregenerated legs, cerci, genital plates, and/or body size. In males, there were no also no apparent trade-offs with respect to antennae, eyes, defensive glands, nonregenerated legs, cerci, or testes, but males that regenerated a leg were larger (but not heavier) than nonregenerating males. Future work at the physiological level will hopefully elucidate the nature of acquisitionallocation trade-offs in phasmids, and how such trade-offs may have shaped their evolution.

The Neotropical Heliconius butterflies are well known to supplement their nectar diet by active pollen collecting. They extract proteins and free amino acids from pollen grains, exhibiting a particular behavior that involves the use of a fluid of uncertain origin. It has been assumed that this fluid is either regurgitated nectar or saliva, because for anatomical reasons a butterfly is able to release only these two fluids through its proboscis. In an experimental approach, 27 individuals of Heliconius melpomene (L.) were given red-dyed sugar solution and subsequently we observed whether the fluid used in pollen feeding was dyed or not dyed. Because regurgitated nectar should contain sugar, fluid samples were taken from the proboscis of butterflies from natural populations in Costa Rica. Samples of 44 individuals from seven species were tested for the presence of fructose and glucose with the aid of aniline phthalate. This study is the first detailed investigation of the origin of the fluid used by Heliconius butterflies in pollen feeding. The results are discussed in terms of already existing hints in literature concerning the true nature of that fluid.

The German yellowjacket, Vespula germanica (F.) (Hymenoptera: Vespidae), is a highly invasive wasp that exhibits efficient mechanisms while foraging. Plastic cognitive systems might be advantageous for invasive species given that they repeatedly encounter dynamic, unknown, or unpredictable environments. In this study, we explore memory dynamics of wasp foragers dealing with changing contexts. The aim of this work was to analyze how learning a second task interferes with the retrieval of a first learned task. We demonstrate that V. germanica wasps integrate old and new memories while foraging on nondepleted food sources. Learning a second task interferes with a first learned task when both tasks have different response requirements, probably due to response competition. Memories associated with the first learned task are not wiped out. Interestingly, this pattern of memory interference does not change when decreasing the number of feeding trials. This study provides new evidence about the complex cognitive mechanisms of V. germanica wasps, which integrate old and new experiences after very few learning episodes. To our knowledge, this is the first study on memory interference in social wasps.

Lepidopteran larvae possess two pairs of styloconic sensilla located on the maxillary galea. These sensilla, namely, the lateral and medial styloconic sensilla, are each composed of a smaller cone, which is inserted into a style. They are thought to play an important role in host plant selection and are the main organs involved in feeding. Ultrastructural examination of these sensilla of fifth instar Lymantria dispar (L.) larvae reveal that they are each ≈70 µm in length and 30 µm in width. Each sensillum consists of a single sensory peg inserted into the socket of a large style. Each peg bears a slightly subapical terminal pore averaging 317 nm in lateral sensilla and 179 nm in medial sensilla. Each sensillum houses five bipolar neurons. The proximal dendritic segment of each neuron gives rise to an unbranched distal dendritic segment. Four of these dendrites terminate near the tip of the sensillum below the pore and bear ultrastructural features consistent with contact chemosensilla. The fifth distal dendrite terminates near the base of the peg and bears ultrastructural features consistent with mechanosensilla. Thus, these sensilla each bear a bimodal chemo-mechanosensory function. The distal dendrites lie within the dendritic channel and are enclosed by a dendritic sheath. The intermediate and outer sheath cells enclose a large sensillar sinus, whereas the smaller ciliary sinus is enclosed by the inner sheath cell. The neurons are ensheathed successively by the inner, intermediate, and outer sheath cells.

Porthetes hispidus (Roheman) (Coleoptera: Curculionidae: Amorphocerini) is thought to be the primary pollinator of and is completely host specific to Encephalartos firiderici-guilielmi Lehmann, which is considered threatened. It is distributed across the Eastern Cape of South Africa. Here, genetic diversity and structure of a cycad-associated weevil, P. hispidus, was investigated using the cytochrome oxidase I (COI) and elongation factor la genes (EF-1α). Samples were taken from nine populations on isolated colonies of the host plant from across its known range. Nucleotide and haplotype diversity were moderate to high. Little to no phylogeographic structure was found, and very low values of F_ST and high values of Nm (COI: F_ST = 0.0759, Nm = 3.04; EF-1α: F_ST = -0.0175, Nm = ∞) indicated high levels of gene flow despite current geographical disjunctions. These data suggest that isolated colonies of E.friderici-guilielmi maintain a viable population of pollinators. However, more rapidly evolving markers may reveal current genetic differentiation that did not exist in the past.

Aedes albopictus (Skuse) (Diptera: Culicidae) is an invasive, container-inhabiting mosquito that was introduced into North America from Japan in 1985. Although previous studies using neutral biochemical markers have found high levels of population differentiation across both the North American and global distribution of Ae. albopictus, relatively little is known regarding evolutionary differentiation of life history traits underpinning fitness. We performed common-garden and line-cross experiments to examine the genetic differentiation of fitness (r')and underlying performance traits at three spatial scales: 1) local (among populations within Florida), 2) regional (between populations from Florida and New Jersey), and 3) long distance (between populations from Florida and Hawaii, Malaysia, and Japan). We found that North American populations (Florida and New Jersey) had lower fitness (r') than populations from outside North America (Hawaii, Malaysia, and Japan). Bivariate means of female, but not male, pupal mass and developmental time differed among regions (Florida, New Jersey, outside North America). Larval survivorship did not differ among regions nor among populations within regions, whereas size-specific fecundity varied among populations within regions but not among regions. Population crosses resulted in significant heterosis and outbreeding depression Of F₁ hybrids but the results of crossing did not depend on the geographic distance separating parental populations in a consistent manner. Together, our results imply a role for local genetic drift affecting the life-history differentiation of Ae. albopictus populations. These conclusions corroborate previous studies of population structure based on neutral biochemical markers.

Chemical cues play a major role in the process of host selection by parasitoids, a process that has been discriminated into several steps such as habitat location, host location, and host acceptance. Egg parasitoids are known to rely on infochemicals of the adult host stage, e.g., pheromones, rather than cues emitted by the inconspicuous host eggs themselves. Here, we show that three different Trichogramma (Hymenoptera: Trichogrammatidae) species were attracted to the synthetic sex pheromone of the olive, Olea europea L., pest Prays oleae (Bern) (Lepidoptera: Yponomeutidae). In Y-tube olfactometer experiments, we revealed differences in the behavior of four tested Trichogramma strains to different concentrations of the host pheromone. Although wasps of Trichogramma oleae (Voegele & Poitale) (IO47) were significantly attracted to two concentrations of the host pheromone, another strain of the same species (IO24) did not show a response to any offered concentrations. Trichogramma cacoeciae Marchai females showed greatest attraction toward the pheromone to three of five offered concentrations. Bioassays with Trichogramma bourarachae Pintureau & Babault wasps showed a positive response of the parasitoids to three concentrations of the host pheromone. Detection of the moth sex pheromone may result in an enhanced searching effort by Trichogramma wasps in an area with host eggs and eventually lead to an increased parasitism rate of these eggs. The results of this research should help enhancing the efficacy of the use of Trichogramma wasps as biocontrol agents against the olive pest.

We provide qualitative and quantitative data on the natural history and foraging behavior of the ground-dwelling ant Odontomachus chelifer (Latreille) (Formicidae: Ponerinae) in a forest reserve in southeastern Brazil, with emphasis on colony activity rhythms and diet preferences in relation to seasonal availability of potential food items in the leaf litter. Ant colonies exhibited nocturnal activity throughout the year, and they foraged significantly more intensively in the wet/ warm (November–March) than in the cold/dry season (April–October). As the night begins, small groups of workers disperse and hunt individually on a wide diversity of litter arthropods of variable sizes. At dusk, encounters with foragers of the diurnal ponerine Pachycondyla striata Fr. Smith were conspicuously avoided by O. chelifer, which occasionally had their prey robbed by the former or were even taken as prey themselves. Termites were the preferred prey of O. chelifer, making up 40% of the food items captured in each season. Seasonal comparisons of prey organisms captured by O. chelifer, and of litter-dwelling arthropods sampled in pitfall traps, revealed that the frequency distribution of retrieved prey in each taxonomic group did not differ seasonally, despite the 2.7-fold increase in the overall availability of litter arthropods in the warm/wet period. This result supports foraging theory by showing that preference for certain animal prey types (i.e., taxonomic groups) persists through time despite seasonal fluctuations in the overall availability of potential prey on the forest floor. This study points out to the importance of studying ant foraging ecology and diet preferences in a natural context.

Tunnel volumes excavated by laboratory groups of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), and the eastern subterranean termite, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) were measured by using two-dimensional foraging arenas. Group sizes of 20, 40, 60, 80,100, and 200 termites were used for the study. Analysis of the images of tunnels taken hourly showed tunnel volume increased and eventually reached equilibrium for both termite species, but Co. formosanus reached the equilibrium faster at lower volume than R. flavipes. Co. formosanus constructed fewer primary tunnels with less branching than R. flavipes and no additional tunneling activity was observed once the tunnel volume reached equilibrium. R. flavipes, however, continued tunnel excavation even after reaching equilibrium, but the equilibrated volume was maintained by filling unused tunnels with sand excavated from newly dug tunnels. For each termite species, the tunnel volume equilibrium was proportional to the group size. The mean individual tunnel volume (mm3 per termite ± SE) of all group sizes computed over the whole experiment was significantly higher for R. flavipes (198.58 ± 1.21) than for Co. formosanus (84.24 ± 0.59). The shape of the growth curves for tunnel volumes indicated the presence of a double feedback system for termite tunneling activity, and we suggest that the positive relationship between nest and population size previously reported for numerous termites species is the result of the self-organized nest-building activity.