High-frequency components in the distress stridulation of Chilean endemic velvet ants (Hymenoptera: Mutillidae)

Abstract. The emission of distress stridulation is a common defense mechanism among insects, including species from the order Hymenoptera (ants, bees and wasps). Wasps from the family Mutillidae (also known as velvet ants) emit audible distress stridulations when attacked. While species-specific variation in the acoustic properties of velvet ants stridulation has been described, one common theme across species is the absence of ultrasonic frequency components (> 20 kHz). We recorded and analyzed the distress stridulation emitted by females of three species of Chilean endemic velvet ants, popularly known as panda ants: Euspinolia chilensis (Spinola, 1851), E. militaris (Mickel, 1938) and Reedomutilla gayi (Spinola, 1851). In general, the stridulation emitted by R. gayi is similar to the distress signal of other velvet ant species described to date. In contrast, the distress signals of both Euspinolia species differ from previously reported Mutillidae stridulations, including the presence of high-frequency spectral components, reaching the ultrasonic range. Due to the scarce information on the natural predators of South American velvet ant species, the defensive significance of distress stridulation having ultrasonic components remains unknown, however, its potential role against reptile and rodent predators is discussed and its potential role as intra-specific communication is suggested

Sensorialidad vibratoria en tabaco: respuestas químicas y efectos sobre la producción foliar

Tesis entregada a la Universidad de Chile en cumplimiento parcial de los requisitos para optar al grado de Magíster en Ciencias Biológicas.La capacidad de percibir y responder a los estímulos físicos, tales como las señales vibracionales (SV), es fundamental para la supervivencia de los seres vivos. El rol de los sentidos y la comunicación animal han sido ampliamente estudiados; sin embargo, en las plantas esta área de investigación se encuentra en una etapa temprana de desarrollo y se necesitan estudios más completos para comprender la ecología de las SV en las plantas, y especialmente para evaluar su importancia adaptativa. Estudiamos si las plantas de tabaco (Nicotiana tabacum) pueden responder químicamente a SV producidas por orugas de la polilla de la papa (Phthorimaea operculella), si la respuesta varía entre orugas y SV, y si esta respuesta implica costos en términos de producción foliar (número de hojas) para la planta. Las plantas de tabaco fueron expuestas a una oruga o al playback (reproducción) de SV de una oruga y luego se cuantificaron las defensas químicas inducidas (alcaloides) mediante cromatografía de gases acoplada a espectrometría de masas (GC-MS). Los niveles de nicotina fueron similares en las plantas de los tratamientos oruga y playback y en ambas más altos que en las plantas control. Esto indica que, al menos para el tabaco, el estímulo vibratorio de una oruga alimentándose es suficiente para producir una respuesta química similar a la provocada por toda la oruga. La producción foliar no difirió entre los tratamientos, probablemente porque las plantas no tenían un recurso limitante en las condiciones de crianza. Este estudio incrementa la comprensión actual sobre la comunicación y las capacidades sensoriales de las plantas, enfatizando el valor adaptativo de las SV para estos organismos y aumenta la comprensión de la comunicación vibracional entre insectos y plantas.The ability to perceive and respond to physical stimuli, such as vibrational signals (VS), is critical for the survival of living beings. The role of senses and communication in animals has been widely studied; however, in plants this research area is at an early stage of development and more comprehensive studies are needed to understand the ecology of VS in plants, and especially to evaluate their adaptive importance. We studied whether tobacco plants (Nicotiana tabacum) can chemically respond to VS produced by caterpillars of the potato moth (Phthorimaea operculella), whether the response varies between feeding caterpillars and only VS, and whether this response involves costs in terms of leaf production (number of leaves) for the plant. Tobacco plants were exposed to either a caterpillar or to the playback of the VS produced by a caterpillar and then chemical induced defenses (alkaloids) were quantified by gas chromatography – mass spectrometry (GC-MS). Nicotine levels were similar in plants of the caterpillar and playback treatments and in both higher than in control plants. This indicates that at least for tobacco, the vibrational stimulus of a chewing caterpillar is sufficient to produce a chemical response similar to that provoked by the whole caterpillar. Leaf production did not differ between treatments, probably because plants did not have a limiting resource in the rearing conditions. This study adds to the current understanding of the communication and sensory abilities of plants, by emphasizing the adaptive value of VS to these organisms and adds to the understanding of insectplant vibrational communication.Red Latinoamericana para la Investigación en Compuestos Naturales Bioactivos (LANBIO) y Fundación Guillermo Puelma

Response to selected ecological parameters by Leptus hringuri Haitlinger, 2000 larvae (Trombidiformes: Erythraeidae) parasitizing treehoppers (Hemiptera: Membracidae) from Bolivia on two host-plant species

Larvae of Leptus hringuri parasitizing families (adult female + offspring) of the treehopper Alchisme grossa on two host-plants, Brugmansia suaveolens (BS) and Solanum ursinum (SU), were studied. The effect of microenvironmental abiotic conditions (luminosity, temperature and relative humidity) and biotic conditions (distance from the soil to a treehopper host and host-plant phenological stage) on this tritrophic interaction was examined. Overall, the results suggest i) intensity of mite infestation (mean number of mites per infested female or family) of treehoppers (insect hosts) was twice on SU than on BS, ii) a preference of L. hringuri larvae for places with more luminosity (on both host-plants) and relative humidity (on SU), iii) a negative correlation between larval infestation and distance of the host colony to the ground, and iv) that larvae of L. hringuri could detect cues (i.e. chemical) emitted by their insect hosts or the host-plant of the insect host. Results indicate that luminosity, humidity and distance to the ground of the insect-host microenvironment affect both parasitization and prevalence of Leptus larvae mites; however, further research will be needed to understand the ecological mechanisms and consequences of these interactions and to test the hypotheses proposed herein under a chemical ecology perspective.Latin American Network for Research on Bioactive Natural Compounds (LANBIO) program - International Science Program (ISP) BOL-01 program - International Science Program (ISP

Natural selection in the tropical treehopper Alchisme grossa (Hemiptera: Membracidae) on two sympatric host-plants

The pronotum is the most distinctive and representative structure in treehoppers. Although several functions have been proposed for this structure, its involvement in fitness has not been formally evaluated. Given the high degree of maternal investment exhibited by the subsocial membracid Alchisme grossa (Hoplophorionini), the pronotum has been suggested as a shield for offspring protection. We performed selection gradient analyses on A. grossa in order to evaluate how natural selection is acting upon two traits associated with this structure considering three different fitness proxies: (1) number of eggs, (2) the ratio between the number of first-stage nymphs and the number of eggs (early survival), and (3) the number of third-stage nymphs (late survival). Since A. grossa feeds, oviposits and mates on two alternative host-plants (Brugmansia suaveolens and Solanum ursinum, both Solanaceae), we also evaluated and compared selection gradients between these host-plants. We found positive linear selection acting upon pronotum length considering the number of eggs and the late survival fitness proxies and positive linear selection acting on the distance between the suprahumeral horns considering the early survival proxy on females ovipositing on both host-plants. These results highlight the importance of the pronotum in treehoppers females' fitness and suggest that maternal care appears to have a greater importance in the way that natural selection is operating than the host-plant where oviposition occurs.LANBIO (Latin American Network for Research on Bioactive Natural Compounds) International Foundation for Science (IFS

Demographic and performance effects of alternative host use in a Neotropical treehopper (Hemiptera: Membracidae)

The mechanisms which promote divergence in populations of phytophagous insects using alternative hosts depend on the characterization of hosts as different selective scenarios and the modeling of the demographic dynamics of the insect on those hosts. In the Bolivian Yungas forests, the treehopper Alchisme grossa (Hemiptera: Membracidae) utilizes two sympatric Solanaceae hosts, Brugmansia suaveolens and Solanum ursinum. On both hosts, females take care of nymphs during their development and adults use almost exclusively their natal host species. We characterized: 1) the performance of families (mother and nymphs) on both hosts, 2) maternal care across families and hosts, 3) biotic (herbivory, predators and parasites) and abiotic (temperature, relative humidity and luminosity) conditions across hosts and 4) demographic parameters of cohorts living under natural conditions on both hosts using matrix population modelling. The life cycle was longer on B. suaveolens than on S. ursinum. Microenvironmental abiotic and biotic traits differed between hosts. Nevertheless, performance did not differ between hosts and no differences between hosts were found in demographic parameters. None of the environmental variables explained the demographic parameters. Females performed maternal care with the same intensity on both hosts. Taken together with published data on the system, these results suggest that individuals of A. grossa in this study belong to a single population. Colonization of one of these hosts might be a recent event and evolutionary processes that promote ecological adaptation and hence demographic or performance differences have not yet become noticeable

SIUC-Viruela del Mono

This project seeks to study the relationship between behavioral immune system activation on reproductive strategies in men who have sex with men. This takes into account the context of the risk of infection by the contagion of monkeypo

Biology and ecology of alchisme grossa in a cloud forest of the Bolivian Yungas

Treehoppers (Membracidae) exhibit different levels of sociality, from solitary to presocial. Although they are one of the best biological systems to study the evolution of maternal care in insects, information on the biology of species in this group is scarce. This work describes the biology and ecology of Alchisme grossa (Fairmaire) (Hemiptera: Membracidae) in a rain cloud forest of Bolivia. This subsocial membracid utilizes two host-plant species, Brugmansia suaveolens (Humb. & Bonpl. ex Wild) Bercht. & J.Presl and Solanum ursinum (Rusby) (both Solanaceae), the first one being used during the whole year and the second one almost exclusively during the wet season. The development of A. grossa from egg to adult occurred on the plant where eggs were laid. Maternal care was observed during the complete nymphal development, and involved behavioral traits such as food facilitation and antidepredatory defense. Life cycle was longer on B. suaveolens during the dry season and shorter on S. ursinum during the wet season. Mortality was similar on both host plants during the wet season but was lower on B. suaveolens during the dry season. The presence of a secondary female companion to the egg-guarding female individual and occasional iteropary is also reported

Biology, ecology and demography of the tropical treehopper Ennya maculicornis (Hemiptera: Membracidae): relationships between female fitness, maternal care and oviposition sites

1. Treehoppers (Hemiptera: Membracidae) exhibit a wide range of social behaviours related to maternal care and nymphal aggregation. Maternal care represents an investment in terms of time and energy leading to trade-offs which bear a strong relationship with parity and can thus affect population dynamics. These trade-offs can be modulated by biotic and abiotic features of the oviposition site. 2. Preliminary observations on Ennya maculicornis (Membracidae: Similinae: Polyglyptini) show that females generally lay a single egg mass, and occasionally two or three egg masses, and that maternal care is a plastic trait because some females abandoned their egg mass before it hatched while other females remained with their offspring after egg hatching. These features make this species an interesting model to study the relationship between female fitness, maternal care and ecological factors such as oviposition site. 3. The biology and natural history of E. maculicornis are described and the relationships in question analysed using demographic parameters estimated by matrix models. Ennya maculicornis showed sexual dimorphism and a longer developmental period than other species of the same tribe. Females exhibited maternal care that increased offspring survival, and preferred mature over young host leaves for oviposition. Finite rate of increase (lambda) values were lower than 1, suggesting a tendency towards population decrease. 4. The results represent the first detailed description of the life history and ecology for a species of this genus. Additionally, new hypotheses for treehopper sexual dimorphism, oviposition site choice and the ecological effects on population dynamics are proposed.Latin American Network for Research on Bioactive Natural Compounds (LANBIO) International Foundation for Science (IFS) grant D/5472-

Kin recognition in a subsocial treehopper (Hemiptera: Membracidae)

© 2018 The Royal Entomological Society 1. Insects exhibiting parental care usually can discriminate between kin and non-kin individuals, allowing parents to avoid investment in foreign offspring. 2. This study investigated the occurrence of kin recognition in the sap-feeding insect Alchisme grossa Fairmaire (Membracidae) through bioassays assessing median female distance to nymphs and degree of nymphal aggregation. Each bioassay involved groups consisting of a female and a cohort of kin or non-kin nymphs (mother and non-mother treatments, respectively). Furthermore, cuticular non-volatile compounds were extracted from nymphal cohorts, analysed by gas chromatography-mass spectrometry and compared between cohorts. 3. In both treatments, nymphs performed a ‘rocking behaviour’ which appears to be correlated with aggregation. Temporal patterns of degree of nymphal aggregation and median female–nymph distance differed between treatments, the former parameter being higher in the mother treat

Reproductive and brood-rearing strategies inAlchisme grossa(Hemiptera: Membracidae): genetic analyses of kinship relationships

Alchisme grossa is a treehopper species showing maternal care until at least the third nymphal instar. A secondary female treehopper has frequently been observed near a family (primary female guarding its egg clutch). Intraspecific brood parasitism, communal breeding or alloparental care may be suggested as possible mechanisms to explain secondary female presence. To distinguish between these phenomena, we performed relatedness analyses of genetic samples of groups including one A. grossa primary female, a secondary female and the associated offspring using polymorphic microsatellites. Furthermore, we characterized the behavioral interaction between both females during maternal care and the reproductive strategy (monandry or polyandry) of A. grossa females by estimating the number of male parents. We observed the presence of secondary females in 35.9% of monitored families. The behaviors characterized suggest the occurrence of brood parasitism in the interaction between both females. Nevertheless, all offspring within a family were descendants only of the primary female and a single male, thus showing that A. grossa females are monandrous. The results, taken together with data on the reproductive biology reported for other treehoppers, are consistent with the occurrence of brood parasitism in A. grossa.ISP (International Science Program at Uppsala University) program BOL-01 LANBIO (Latin American Network for Research on Bioactive Natural Compounds) program International Foundation for Science D/5472-1 CONICYT PIA Apoyo CCTE AFB17000