Gallery Systems Research Articles

Immature stages of Phloeosinus tacubayae (Curculionidae: Scolytinae): morphology and chaetotaxy of larva and pupa, sexual dimorphism of adults, and developmental time.

The current knowledge of morphology and chaetotaxy of the different developmental stages within the subfamily Scolytinae presents an information deficit that needs to be addressed. Thus, the objective of the present study was to describe, the chaetotaxy and morphology of larvae and pupae, and determine the number of larval instars, the sexual dimorphism in adults, and the development time in Phloeosinus tacubayae. The number of larval instars was determined using traditional morphometry of cephalic capsule and multivariate analysis; description of morphology and chaetotaxy of larvae and pupae, and sexual dimorphism in adults was based on light microscopy and scanning electron microscopy photographs; finally, we quantified development time by mean reviews of 10 gallery systems selected randomly in infested logs, in the laboratory. Morphometric analysis of the cephalic capsule allowed the recognition of 3 different instars. Our results showed that the larvae of P. tacubayae have unique attributes in the body that differentiate them from other genera of the subfamily for example the epicranial suture is not marked, and differentiated from Phloeosinus canadensis, such as a smaller number of setae in the maxillae and without a tergal plate. The pupa had a smaller number of setae on the whole body. The most useful morphological characters to identify a sexual dimorphism in adults were found in the shape and relative position of the seventh and eighth tergites; development time lasted 40 days in total, being the pupal stage the one that took the longest to complete.

TManual: Assistant for manually measuring length development in structures built by animals.

Structures built by animals are extended phenotypes, and animal behavior can be better understood by recording the temporal development of structure construction. For most subterranean and wood-boring animals, these structures consist of gallery systems, such as burrows made by mice, tunnel foraging by termites, and nest excavation in ants. Measurement of the length development of such structures is often performed manually. However, it is time-consuming and cognitively costly to track length development in nested branching structures, hindering the quantitative determination of temporal development. Here, I introduce TManual, which aids the manual measurement of structure length development using a number of images. TManual provides a user interface to draw gallery structures and take over all other processes handling input datasets (e.g., zero-adjustment, scaling the units, measuring the length, assigning gallery identities, and extracting network structures). Thus, users can focus on the measuring process without interruptions. As examples, I provide the results of the analysis of a dataset of tunnel construction by three termite species after successfully processing 1125 images in ~3 h. The output datasets clearly visualized the interspecific variation in tunneling speed and branching structures. Furthermore, I applied TManual to a complex gallery system by another termite species and extracted network structures. Measuring the lengths of objects from images is an essential task in biological observation. TManual helps users handle many images in a realistic time scale, enabling a comparative analysis across a wide array of species. TManual does not require programming skills and outputs a tidy data frame in CSV format. Therefore, it is suitable for any user who wants to perform image analysis for length measurements.

Number of gallery arms of the tree-killing bark beetle Polygraphus proximus (Coleoptera: Curculionidae: Scolytinae)

• Gallery length increased as the number of gallery arms in a gallery system increased. • Polygraphus proximus laid more eggs in two-armed galleries than in one- and three-armed ones. • Galleries with more than two arms did not have more eggs compared to two-armed ones. • Gallery length with no oviposition increased as the number of gallery arms increased. • The optimal number of arms (in terms of the number of eggs oviposited) might be two. Polygraphus proximus Blandford (Coleoptera: Curculionidae: Scolytinae) is a non-aggressive monogynous bark beetle that has caused mass mortality in fir ( Abies spp.) forests in the last decade. Although gallery structures made by polygynous beetles may influence their reproductive success, the gallery structure and the number of eggs laid by the monogynous tree-killing bark beetle P . proximus has not been investigated in detail in the natural setting of their native range. We, therefore, investigated the length of mother galleries of P . proximus and the number of eggs oviposited by the beetles in relation to gallery systems with different numbers of arms. The number of eggs oviposited in two-armed galleries was significantly greater than that observed in one- and three-armed galleries. Additionally, the length of one- or two-armed galleries with no oviposition was significantly shorter than that in galleries consisting of more than two arms. Our data may suggest that the optimal number of arms in a gallery system (in terms of the number of eggs oviposited) was two.

Synonymy of soil-feeding termites Pseudocapritermes sowerbyi and Pseudocapritermes largus, with evidence from morphology and genetics

• Drawing of morphological characters for measurement on Pseudocapritermes. • Description and comparison of two species of Pseudocapritermes on morphological characters. • Sequencing and analysis of full-length genes of COI , COII , and 16S rRNA. • Confirmed the close relationship between Pseudocapritermes and Sinocapritermes. Pseudocapritermes Kemner is a termite group that constructs subterranean gallery systems in topsoil. This genus is distributed in the Oriental region and contains 18 species. Dependence on the morphological measurements of soldiers makes the taxonomy of Pseudocapritermes difficult. In this study, we compared morphological characters of soldiers and adults of P. largus and P. sowerbyi . In addition, three fulllength mitochondrial genes ( COI , COII , and 16S rRNA ) were sequenced from a total of eight P. largus and P. sowerbyi colonies. Morphological comparison of soldiers showed that P. largus is larger than P. sowerbyi , but there was overlap in some measurements. In adults, the morphological characters of P. largus were congruent with those of P. sowerbyi . Sequence alignments of COI , COII , and 16S rRNA revealed a high pairwise genetic identity (ranging from 99.64 to 100%) between the two species, which suggested that P. largus and P. sowerbyi are the same species. Molecular phylogenetic analysis based on COII revealed that Pseudocapritermes belongs to the Termes group having soldiers with asymmetrical snapping mandibles and is more closely related to Sinocapritermes than to other Termes group genera distributed in China. Morphological similarity and genetic identity indicate that P. largus is a junior synonym of P. sowerbyi .

Green method of stemming the tide of invasive marine and freshwater organisms by natural filtration of shipping ballast water

Marine and freshwater pollution caused by transport of invasive species in shipping ballast water is a major global problem and will increase in magnitude as shipping of commodities increases in the future. An economical method to preclude biological organisms in the seawater used for ballast is to exclude them at the source port. Integrated natural filtration using onshore wells or seabed gallery systems has been thoroughly investigated for use as pretreatment for seawater desalination systems and has proven to be environmentally acceptable and economic. Thus, the use of this proven filtration technology to another issue, ballast water treatment, is an innovative method of providing marine organism free seawater by non-destructive means in port-based facilities. This method is ecosystem-friendly in that no chemicals or destructive processes are used. Design and construction of well or seabed gallery intake systems for production of ballast seawater are feasible in virtually all global port facilities.

La situación de las galerías drenantes en la Región de Murcia: un indicador de la calidad ambiental del territorio

Se presenta una investigación sobre la situación de los sistemas de galerías de agua, del tipo mina horizontal con pozos verticales, en la Región de Murcia. El trabajo parte de la hipótesis referente al paulatino deterioro de estos complejos, exponente del patrimonio hidráulico generado en este territorio a lo largo de los siglos. El objetivo principal reside en analizar el estado de estas construcciones y determinar su funcionalidad actual. A través del trabajo de campo, la consulta a diferentes fuentes de información como Confederación Hidrográfica del Segura y los resultados expuestos por la literatura especializada, se corrobora la hipótesis de partida, ya que más de la mitad de las galerías de agua se muestran sin uso y en estado de ruina, afectadas por la sobreexplotación de los acuíferos y el abandono del medio rural. Sin embargo, los sistemas funcionales suman un caudal anual de 13 Hm3, una cifra bastante significativa en un área de clima semiárido y escasas aguas superficiales. Estos recursos siguen manteniendo diversos espacios de regadío tradicional de forma sostenible y constituyen un indicador de la calidad ambiental que todavía conservan distintos espacios del Sureste de la Península Ibérica.

First record of Ektaphelenchoides pini associated with Ips sexdentatus on Pinus nigra laricio in Italy

AbstractIn February 2015, an unexpected windstorm downed five hectares of a European black pine Pinus nigra subsp. laricio forest formation located close to Vallombrosa, Florence (Central Italy). In the following spring, an extensive survey was conducted in the area. Felled trees, stumps and all the suitable plant material were screened for the presence of the pinewood nematode (PWN), Bursaphelenchus xylophilus, by sampling wood and bark. Bark beetles were then collected from the gallery systems on the inner side of bark samples and observed in the laboratory. The following bark beetles were morphologically identified: Ips sexdentatus, Orthotomicus erosus, O. laricis and Pityogenes bidentatusa. The dissection of Ips sexdentatus allowed the extraction of numerous nematodes that were morphologically and molecularly identified as Ektaphelenchoides pini. Conversely, only few nematode specimens were isolated from either pine bark or wood. These individuals could be only molecularly identified and belonged to an undescribed nematode taxon. Even though no PWN was recorded in the investigated sites, our survey allowed the detection of a new association between E. pini and I. sexdentatus on P. nigra.

Galerías de agua en el campo alto de Lorca (Región de Murcia). Análisis y caracterización territorial

En este trabajo se analizan los principales sistemas tradicionales de acopio de agua localizados en el campo alto de Lorca. Ingenios de captación del tipo galería drenante o qanat, cuyos recursos se han destinado para usos locales de estas pedanías, tanto para abastecimiento de boca como regadío. Sin embargo, el caudal de algunos afloramientos permitió que, durante siglos, parte de sus aguas se destinaran a abastecer a la población de la capital, por medio de kilométricas redes de distribución. El trabajo de campo y la documentación de archivo han sido esenciales en esta investigación, donde se pone de manifiesto el esfuerzo secular de comunidades asentadas en un territorio de clima semiárido y escasos recursos superficiales. Los resultados muestran la existencia de numerosas galerías de agua, con elementos y funciones similares a otros ejemplos del Sureste de España, aunque con factores espaciales e históricos singulares. No es posible entender la configuración de este paisaje rural si no se conoce la influencia territorial que, a lo largo del tiempo, han jugado los sistemas de galerías horizontales; construcciones que, en muchos casos, siguen funcionales, conservadas y mantenidas por la población local.

The European spruce bark beetle Ips typographus (L.) in wind-damaged stands of the eastern part of the Tatra National Park – the population dynamics pattern remains constant

Abstract In March 2017, in the eastern part of the Tatra National Park in Poland, large windthrowns affected the passively and actively protected Norway spruce Picea abies stands. In early 2018, a set of 12 small research plots (20 trees on each plot) was established in the Norway spruce stands next to the windblown area – 6 in the stands under active nature protection (broken and fallen trees processed in 2017), and 6 in the stands under passive nature protection (trees left on the ground). Living trees on the plots were regularly checked during the growing season in order to identify and register the spruces infested by Ips typographus, which were dissected in 2 or 4 half-meter sections. 155 spruces (64%) infested by I. typographus were recorded on all 12 plots: 118 out of 120 (98%) in passive and 37 out of 120 trees (31%) in active protection. Mean infestation density calculated on 128 samples from 47 trees was higher under passive than under active protection (1.23 and 0.92 mating chamber per 1 dm2, respectively). Among 1709 gallery systems, those with 2 maternal galleries prevailed (63.0%); the mean share of females was higher in passive than in active protection zone (63.1 and 59.6% respectively). The mean number of progeny per one female was higher in active than in passive protection zone (20.23 and 19.12 respectively). I. typographus attack on standing trees had lower intensity in the stands previously subjected to the processing and removal of fallen and broken trees, which indicates positive effect of implemented active protection procedures. The parameters describing I. typographus population on attacked trees, as well as low activity of natural enemies, demonstrate its reproduction potential and resulting high risk of a new outbreak, according to the pattern known earlier from the other areas in Poland and Europe.

Plant Pathogenic Fungi Associated with Coraebus florentinus (Coleoptera: Buprestidae) Attacks in Declining Oak Forests

The black-banded oak borer, Coraebus florentinus, is an emerging pest of oak trees in the western Mediterranean region. Larvae of the insect are xylophagous and progressively excavate an annular gallery that interrupts sap flow, resulting in the death of the attacked branches. Until now, limited information has been available regarding the ecological interactions between C. florentinus and the main plant pathogenic fungi involved in the etiology of oak decline. Knowledge of these interactions is important in understanding their impact in natural ecosystems and developing appropriate management strategies. Therefore, in this study, we characterized the fungal communities occurring in the exoskeleton of adults and larvae of C. florentinus and associated with the necrotic wood tissues surrounding the branch galleries of declining oak trees. A total of 29 fungal species were identified based on DNA sequence data and morphological features, of which 14 were from symptomatic woody tissues, six from insect exoskeleton, and nine from both insects and symptomatic wood tissues. The most frequent fungal species, Cryphonectria naterciae (15.9% of isolates), Dothiorella iberica (11.3%), and Diplodia corticola (9.9%), were isolated from both insect and gallery systems. All three species are well-known oak pathogens and are reported here, for the first time, to be associated with C. florentinus. At the same time, 89.6% of the fungal taxa were isolated from one or two sites, highlighting the site-dependence of fungal community assemblages.

Life Cycle and Development of Coptoborus ochromactonus (Coleoptera: Curculionidae: Scolytinae), a pest of balsa.

Coptoborus ochromactonus Smith and Cognato is a recently described xyleborine ambrosia beetle pest associated with balsa, Ochroma pyramidale (Cav. Ex Lam.) Urb., in Ecuador. This pest has caused significant loss of cultivated balsa in Ecuador, but little is known of its biology and ecology. Based on examination of multiple gallery systems, this study describes the gallery pattern and life cycle of C. ochromactonus and confirms the generic identity of the symbiotic fungus. Females initiated attack, excavating a gallery perpendicular to the bole. The primary tunnel branched into a secondary tunnel at a mean 3.13 mm. This first secondary tunnel was excavated in a horizontal plane between the phloem and xylem for a mean 18.0 mm. Along its length, two tertiary tunnels were constructed on each side, measuring a mean 26.0 and 20.0 mm, respectively. Conidiophores and conidia of an unidentified Fusarium sp. grew on the tunnel walls and were fed upon by the beetle and her progeny. Coptoborus ochromactonus exhibits sexual dimorphism. The female is 2.6 mm long and possesses a round pronotum, whereas the male is 2.2 mm long and has a quadrate pronotum. The developmental stages last a mean 6, 14, 6, 4 and 30 d for egg, larva, pupa, teneral adult, and adult, respectively, when reared at 25°C. Three larval instars were present, with mean head capsule widths of 0.23, 0.31, and 0.42 mm, respectively. In general, the life cycle of C. ochromactonus is similar to those described for other xyleborine ambrosia beetle species.

Numerical modeling for the urban drainage gallery systems design

ABSTRACT Considering the frequent flooding of urban centers, the financial limitations and the inefficient management of Urban Drainage (UD) systems in Brazilian municipalities, it is necessary that projects be developed efficiently. These objectives are achieved with the correct definition of the diameter and galleries slope, resulting in adequate hydraulic ratios. It is also necessary to guarantee the flow without backwater, by verifying the energy grade line along the network. There are software capable of assisting the calculation, which, however, do not report optimized solutions. A vector-based numerical modeling is presented for the optimized sizing of a UD gallery system. This model was applied in an area and its results were compared with those obtained by two software in the Brazilian market. It is demonstrated the optimization developed contributes to increases the efficiency in the design. The main scientific contributions are: to characterize and model the typical design slopes, to obtain the optimum slope combined with the smaller diameter; to explore the potential of the hydraulic ratios above those normally employed, with positive effects on the definition of {D, ig} and the economy in the system; and to implement a recursive solution from a cycle of interdependent information, ensuring accuracy of results.

Bursaphelenchus michalskii sp. n. (Nematoda: Aphelenchoididae), a nematode associate of the large elm bark beetle, Scolytus scolytus Fabr. (Coleoptera: Curculionidae), in Dutch elm disease-affected elm, Ulmus laevis Pall.

Summary Bursaphelenchus michalskii sp. n. is described from the bark of the European white elm, Ulmus laevis. All propagative stages of the nematode were found in larval galleries of the large elm bark beetle, Scolytus scolytus, and in overlapping gallery systems of this species and the small European elm bark beetle, S. multistriatus. Dauer juveniles of the new nematode are transmitted to new breeding trees under elytra of adult S. scolytus. Bursaphelenchus michalskii sp. n. is characterised by the female body length of 953 (838-1108) μm and male body length of 893 (811-971) μm, very slender body (a = 53.9 (46.1-58.5) and 60.9 (52.2-72.0) in female and male, respectively), lateral fields with three incisures (two bands), excretory pore usually located anterior to the median bulb, lack of vulval flap, long post-uterine sac, relatively small spicules 12.3 (10.8-13.3) μm long with no cucullus and with distinct, somewhat thorn-like, dorsally bent or reflexed condylus and a conical or digitate rostrum, and the arrangement of the seven male caudal papillae (i.e., a single precloacal ventromedian papilla (P1), one pair of adcloacal ventrosublateral papillae (P2) at or just anterior to cloacal slit, one ventrosublateral, postcloacal pair (P3) located at ca 60% of the tail length, posterior to cloacal slit, and one pair (P4) of ventrosublateral papillae located near the base of the bursa). The newly described species shares most of the key morphological characters with members of the eremus-group (sensu Braasch et al., 2009). However, B. michalskii sp. n. is unique amongst Bursaphelenchus species by a combination of female tail and spicule shape, excretory pore position, and other morphometric characters. These findings were confirmed by DNA sequencing and phylogenetic analysis of the 18S and 28S rDNA regions and by the unique molecular profile of the ITS region (ITS-RFLP).

Monogamous sperm storage and permanent worker sterility in a long-lived ambrosia beetle

The lifetime monogamy hypothesis claims that the evolution of permanently unmated worker castes always requires maximal full-sibling relatedness to be established first. The long-lived diploid ambrosia beetle Austroplatypus incompertus (Schedl) is known to be highly social, but whether it has lifetime sterile castes has remained unclear. Here we show that the gallery systems of this beetle inside the heartwood of live Eucalyptus trees are always inhabited by a single core family, consisting of a lifetime-inseminated mother, permanently unmated daughter workers, and immatures that are always full siblings to each other and their adult caretakers. Overall sex ratios are even. Males always disperse and only survive as stored sperm, but female offspring either disperse to mate and found their own colony or assume unmated worker roles, probably surviving for many years without any reproductive potential because tarsal loss precludes later dispersal. A well-supported Platypodinae phylogeny has allowed us to infer that parental monogamy evolved before a lifetime-unmated worker caste emerged, confirming the prediction that monogamy and full-sibling relatedness are necessary conditions for the evolution of such workers. The initially very challenging but ultimately long-term stable nesting habitat in live trees appears to have provided the crucial benefit/cost factor for maintaining selection for permanently sterile workers after strict monogamy and lifetime sperm storage had become established in this curculionid coleopteran lineage.

Reproduction abilities of Ips typographus (L.) (Coleoptera: Curculionidae, Scolytinae) in the stands damaged by the wind in 2013 in the Kościeliska Valley (Tatra National Park)

Abstract At the end of 2013, strong wind destroyed spruce stands on large areas of Kościeliska Valley in Tatra Mts. in Poland. In 2015–2017, 304 bark samples were collected from 106 spruces; 25 cm × 25 cm large samples were taken from 2 or 4 sections of infested trees in July/August each year. The infestation density, sex ratio, length of maternal galleries, number of progeny and impact of natural enemies were recorded. The infestation density in individual years was 0.79–0.86 mating chambers per dm2, the average length of maternal gallery (55.2–56.6 mm) did not differ between years, The average number of progeny per female from 3-year pooled data was 18.22, the highest in 2015 (27.4) then collapsed to 15.5–16.8. The gallery systems with 2 females, in which the reproduction success was the highest, dominated (62.6%). The frequency of parasitoids or entomopathogens was very low (2–20% mortality rate in 19 bark samples). Possible reasons of relatively low reproduction success regardless generally favourable breeding conditions and its collapse after first year, such as high infestation density and low survival rate of larvae because of climatic conditions (drought), are discussed. Taking into account the described population features, very intense tree mortality and mechanisms known from the other wind events, further development of the outbreak can be expected in this area.

Geosmithia associated with bark beetles and woodborers in the western USA: taxonomic diversity and vector specificity

ABSTRACTFungi in the genus Geosmithia (Ascomycota: Hypocreales) are frequent associates of bark beetles and woodborers that colonize hardwood and coniferous trees. One species, Geosmithia morbida, is an economically damaging invasive species. The authors surveyed the Geosmithia species of California and Colorado, USA, to (i) provide baseline data on taxonomy of Geosmithia and beetle vector specificity across the western USA; (ii) investigate the subcortical beetle fauna for alternative vectors of the invasive G. morbida; and (iii) interpret the community composition of this region within the emerging global biogeography of Geosmithia. Geosmithia was detected in 87% of 126 beetle samples obtained from 39 plant species. Twenty-nine species of Geosmithia were distinguished, of which 13 may be new species. Bark beetles from hardwoods, Cupressus, and Sequoia appear to be regular vectors, with Geosmithia present in all beetle gallery systems examined. Other subcortical insects appear to vector Geosmithia at lower frequencies. Overall, most Geosmithia have a distinct level of vector specificity (mostly high, sometimes low) enabling their separation to generalists and specialists. Plant pathogenic Geosmithia morbida was not found in association with any other beetle besides Pityophthorus juglandis. However, four additional Geosmithia species were found in P. juglandis galleries. When integrated with recent data from other continents, a global pattern of Geosmithia distribution across continents, latitudes, and vectors is emerging: of the 29 Geosmithia species found in the western USA, 12 have not been reported outside of the USA. The most frequently encountered species with the widest global distribution also had the broadest range of beetle vectors. Several Geosmithia spp. with very narrow vector ranges in Europe exhibited the similar degree of specialization in the USA. Such strong canalization in association could reflect an ancient origin of each individual association, or a recent origin and a subsequent diversification in North America.

Estructura larval de Passalus gravelyi y dimorfismo sexual en larvas de Passalidae.

The adults and larvae of Passalidae are subsocial insects commonly found in tropical forests, living in decaying wood gallery systems constructed by adults. Currently, few repots on the larvae of Neotropical Passalidae have been published and information is scarce. In this study, the Passalus (Pertinax) gravelyi Moreira, 1922 larvae is described for the first time, based on ten larval specimens 1 (1° instar), 4 (2° instar), and 5 (3° instar) associated with three adults collected from a single colony at the Parque Nacional do Itatiaia (Itatiaia, Rio de Janeiro, Brazil). The description was carried out based on electronic and digital photographs of diagnostic structures, with some details on the systematic of the species. The larvae of Passalus gravelyi has the general setal 'Pertinax' pattern and differed from others by 16 to 18 setae on the anal ring, the other larvae data from Brazilian species show the anal ring with 10 to 12 setae. A discussion on the presence of sexual dimorphism in 62 species of two and three instars of Passalidae larvae is provided for the first time. Besides, a description of the terminal ampulla present as a cuticular structure found in the medial-ventral area of the 9th abdominal sternite in males is also given. The terminal ampulla was only observed in the Passalidae male larvae and was not visible in female larvae. The terminal ampulla are acknowledged now in males of 64 passalid species, that are taxonomically distributed in world tropical forests, at the Oriental and Australian subfamily Aulacocyclinae (Aulacocyclini & Ceracupini) and the cosmotropical subfamily Passalinae (Solenocyclini, Macrolinini, Passalini, & Proculini).

Structure and function of subterranean gallery systems of soil-feeding termites Pericapritermes nitobei and Sinocapritermes mushae

Soil-feeding termites are a critical trophic guild comprising more than a quarter of all termite species. Most soil-feeding termites build subterranean and diffuse gallery systems that are difficult to observe. In this study, we excavated the gallery systems of two soil-feeding termite species, Pericapritermes nitobei (Shiraki) and Sinocapritermes mushae (Oshima & Maki). Termite-harboring spaces were clusters of small cells connected with tunnels, with the cells usually adjacent to underground pieces of wood, stone, thick roots, and fibrous roots. Clusters of cells in a gallery system are referred to as nodes. In total, 90 nodes of five P. nitobei colonies and 64 nodes of seven S. mushae colonies were examined. The forager proportion of P. nitobei was the highest in nodes adjacent to fibrous roots, and that of S. mushae was the highest in nodes adjacent to pieces of wood, indicating that organic matter accumulated between the fibrous roots and underneath wood acted as a carbon source for the termites to feed upon. Nursed castes of P. nitobei, including larvae and eggs, were most frequently observed under thick roots and stones, but those of S. mushae were not located under any specific object. The nesting and feeding sites of P. nitobei were separate, but those of S. mushae overlapped. We speculate that the various food sources and their distributions are likely the main selection force for the gallery structures of soil-feeding termites.

Effects of Acute and Chronic Exposure to Predatory Cues on Spatial Learning Capabilities in the Subterranean Rodent Ctenomys talarum (Rodentia: Ctenomyidae)

AbstractSpatial learning, the cognitive ability that allows animals to efficiently locate food, partners or avoid predators, can be affected by various factors such as stress. Stressors represent a threat to the animal's homeostasis and trigger a set of physiological and behavioral changes known as stress response. The herbivorous rodent Ctenomys talarum (tuco‐tuco) inhabits underground complex gallery systems. Dispersal as well as food collection occurs on the surface, where they are exposed to terrestrial and aerial predators. We evaluated the effect of a natural stress factor, predation, on spatial learning of C. talarum. Additionally, we collected data on neutrophil/lymphocyte ratio, hematocrit, blood glucose, and plasma cortisol to assess physiological levels of stress. The acute exposure to direct cues indicating the presence of a predator (immobilization + cat urine) increased the time needed to reach the goal in a longitudinal labyrinth. The number of errors also increased albeit the difference was only marginally significant. The chronic exposure to predator cues (immobilization, cat urine, and cat fur) presented in an unpredictable order significantly increased both time and errors committed by tuco‐tucos during learning trials in the labyrinth. Results show the strong impact of predatory stress on the spatial abilities of C. talarum, a key cognitive process involved in most of their vital activities. They also highlight the importance of investigating wild species as regards the development of antipredatory defensive behaviors that contribute both to the avoidance of deleterious consequences of a direct attack and the influence on food search and mate localization performance.

New ichnotaxon Megascolytinus zherikhini (Coleoptera: Curculionidae: Scolytinae) from upper cretaceous deposits of mongolia

Gallery systems of Scolytinae on a petrified Araucaria trunk fragment from the Late Cretaceous of Gobi, Mongolia, similar to those of extant members of the supertribe Hylesininae, but exceptionally large (estimated body length of the beetle about 20 mm), are described as a new ichnotaxon, Megascolytinus zheriknini.