Semiobiotica de Kinji Imanishi en su obra ‘El mundo de las cosas vivientes’ (III parte): paráfrasis de ‘Umwelt’, en torno a ‘ambiente, sociedad e historia’

Kinji Imanishi was a Japanese who made important contributions to ethology, theoretical biology, and anthropology. The Japanese biologist organized his book "The world of living things" in a total of 5 chapters: 1) similarity and difference, 2) on structure, 3) on environment, 4) on society and 5) on history. Previously, I published two works with interpretations of the first and second chapters of his book. This work is an interpretation of the last three remaining chapters.Kinji Imanishi fue un japonés que hizo importantes aportes a la etología, a la biología teórica y a la antropología. El biólogo nipón organizó su libro “El mundo de las cosas vivientes” en un total de 5 capítulos: 1) similitud y diferencia, 2) estructura, 3) ambiente, 4) sociedad e 5) historia. Anteriormente, publiqué dos trabajos con las interpretaciones correspondientes al primer y segundo capítulos de su libro. El presente trabajo es una interpretación de los tres últimos restantes

Appetence behaviours of the triatomine bug Rhodnius prolixus on a servosphere in response to the host metabolites carbon dioxide and ammonia

A combination of 1,000ppm CO2 plus 30-40ppb NH3 in an air stream induced Rhodnius prolixus nymphs walking on a servosphere to perform a series of appetence behaviours. Shortly after the onset of stimulation the nymphs turned sharply upwind towards the source of the chemostimuli (within 13±9s) from mostly downwind and crosswind walks in the air stream alone. The mean vector angles of these upwind tracks were concentrated in a cone 60° either side of due upwind. The upwind walking bugs stopped more frequently but for a shorter duration and walked at a higher speed than before stimulation. During stops in the presence of the chemostimuli the bugs frequently corrected their course angles and extended their forelegs to reach higher with their antennae in the air. In the air stream alone, R. prolixus nymphs frequently sampled the sphere surface with the antennae and cleaned their antennae with the foreleg tarsi. However, the nymphs only briefly tapped the left or right antennal flagellum on the corresponding first leg tarsus and never touched the servosphere surface in the presence of the chemostimuli. After chemostimulus removal from the air stream the bugs continued to respond with the same appetence responses as during stimulation, but walked more tortuously in a crosswind direction in an effort to regain contact with the chemostimul

Orientation of Belminus triatomines to cockroaches and cockroaches’ fecal volatiles: an ethological approach

Most triatomine bugs (Hemiptera: Reduviidae: Triatominae) are hematophagous, though Belminus species can live off of cockroach hemolymph to complete their life cycle. In this work we described the fixed action pattern (FAP) employed by B. ferroae to identify, approach and suck on a living cockroach. The FAP described here is composed of the following stereotyped behaviors: 1) visual and/or olfactory detection of the cockroach, 2) reaching, 3) cautious approach, 4) antennal exploration, 5) extension of the proboscis, 3) piercing to sedate, 5) walking  away and waiting (post sedation behavior), 6) second cautious approach, 7) extension of the proboscis, 8) piercing to suck hemolymph. In order to identify chemicals cues that could elicit such FAP, we examined the behavior of B. corredori, B. ferroae and B. herreri in response to the cockroaches’ odor, fresh cockroach feces and fresh rodent wastes. The last two sources were tested based on the assumption that abundant chemicals near host refuges could serve as cues for host orientation. We found the cockroach odor emanating from a box significantly attracted B. herreri in a still air olfactometer. The three Belminus species approached the captive cockroach after one hour, but avoided to climb the box. Odors emanating from the cockroach feces attracted B. corredori and B. ferroae in a Y-olfactometer. The FAP sequence observed suggests Belminus bugs are not predators like the rest of reduviids (assassin bugs) —but are kleptophagous ectoparasites, since they do not attack and kill a prey but rather steal hemolymph from its invertebrate host. Triatomines and their hosts have intimately shared the same refuge for millions of years. Similar odors occur across invertebrate and vertebrate refuges, and are recurrent in human abodes, thus plausibly explaining how these kleptophagous bugs can readily switch to the domestic habitat

Historia natural de Camponotus simillimus indianus Forel, 1879 (Hymenoptera: Formicidae): una hormiga domiciliaria en los Andes venezolanos | Natural history of Camponotus simillimus indianus Forel, 1879 (hymenoptera: formicidae): a house infesting ant from the venezuelan Andes

En este trabajo se mencionan algunos aspectos relacionados con la historia natural de Camponotus simillimus indianus (Forel, 1879) según observaciones realizadas en la localidad de Loma de Los Guamos del estado Mérida, en los Andes venezolanos. Se incluyen algunos comentarios taxonómicos acerca de la especie dentro del complejo picipes a partir de la revisión de especímenes depositados en museos y colecciones entomológicas. De acuerdo con observaciones de campo y laboratorio, C. simillimus indianus exhibió un comportamiento subordinado ante especies agresivas, con actividad principalmente nocturna fuera del nido. Se observaron nidos permanentes asociados a infraestructuras humanas, y nidos temporales asociados a áreas silvestres y domiciliares. En entrevistas hechas a los pobladores de la región se registra que el 93% de ellos reconocen a la especie como wachaco o bachaco negro y el 76% la considera una plaga domiciliaria (n = 43). Se discute cómo el carácter estable y temporal de los nidos sugiere la presencia de nidos parentales y satélites en C. simillimus indianus, siendo las colonias satélites las que prevalecen en el domicilio humano. Como aporte a su historia natural, se devela que C. simillimus indianus puede anidar en el hábitat humano y por lo tanto ser considerada como plaga en las regiones rurales de los Andes venezolanos. Palabras clave: Áreas rurales, Camponotini, complejo picipes, hormigas plaga, nidos satélites, Neotrópico, selva nublada, perturbación antrópica. ABSTRACT Some aspects related with the natural history of Camponotus simillimus indianus (Forel, 1879) are mentioned in this work based on observations from the village Loma de Los Guamos in Mérida State, in the Venezuelan Andes. Some taxonomic remarks about the species within the picipes complex are included based on specimens deposited in museums and entomological collections. According with field and laboratory observations, C. simillimus indianus shows subordinate behavior in presence of aggressive species and nocturnal foraging activity. Permanent nests associated with human infrastructures, and temporal nests associate to sylvatic and domiciliary areas were recorded. Surveys of villagers indicate that 93% of the residents recognize this species as “wachaco or bachaco negro”, and 76% of them consider it a house pest (n = 43). Since permanent and temporary nests were observed, we propose the presence of parental and satellite nests in C. simillimus indianus, being the satellite colonies the prevailing agents in the human domicile. Based on its natural history, C. simillimus indianus is able to nest in the human habit and so can be proposed as a house pest in the rural regions of the Venezuelan Andes. Key words: Rural areas, Camponotini, picipes complex, pest ants, satellite nests, Neotropics, cloudy forests, anthropic disturbance

Evolution of Hematophagous Habit in Triatominae (Heteroptera: Reduviidae)

All members of Triatominae subfamily (Heteroptera: Reduviidae), potential vectors of Trypanosoma cruzi, etiologic agent of the Chagas disease, feed on blood. Through evolution, these bugs have fixed special morphological, physiological, and behavioral aptations (adaptations and exaptations) adequate to feed on blood. Phylogeny suggests that triatomines evolved from predator reduvids which in turn descended from phytophagous hemipterans. Some pleisiomorphic traits developed by the reduvid ancestors of the triatomines facilitated and modeled hematophagy in these insects. Among them, mouthparts, saliva composition, enzymes, and digestive symbionts are the most noticeable. However, the decisive step that allowed the shift from predation to hematophagy was a change of behavior. The association of a predator reduvid with nesting vertebrate (≈110 to 32 Ma) permitted the shift from an arthropod prey to a vertebrate host. In this work, we review the phylogeny and dispersion of triatomines and the current controversy over the monophyly or polyphyly of this group. We also discuss how these insects were able to overcome, and even have taken advantage of, diverse ancestral and physical barriers to adapt to sucking blood of nidicolous vertebrates

Water-seeking behavior in worm-infected crickets and reversibility of parasitic manipulation

One of the most fascinating examples of parasite-induced host manipulation is that of hairworms, first, because they induce a spectacular "suicide” water-seeking behavior in their terrestrial insect hosts and, second, because the emergence of the parasite is not lethal per se for the host that can live several months following parasite release. The mechanisms hairworms use to increase the encounter rate between their host and water remain, however, poorly understood. Considering the selective landscape in which nematomorph manipulation has evolved as well as previously obtained proteomics data, we predicted that crickets harboring mature hairworms would display a modified behavioral response to light. Since following parasite emergence in water, the cricket host and parasitic worm do not interact physiologically anymore, we also predicted that the host would recover from the modified behaviors. We examined the effect of hairworm infection on different behavioral responses of the host when stimulated by light to record responses from uninfected, infected, and ex-infected crickets. We showed that hairworm infection fundamentally modifies cricket behavior by inducing directed responses to light, a condition from which they mostly recover once the parasite is released. This study supports the idea that host manipulation by parasites is subtle, complex, and multidimensiona

Identification and Synthesis of a Male-Produced Pheromone for the Neotropical Root Weevil Diaprepes abbreviatus

An unsaturated hydroxy-ester pheromone was isolated from the headspace and feces of male Diaprepes abbreviatus, identified, and synthesized. The pheromone, methyl (E)-3-(2-hydroxyethyl)-4-methyl-2-pentenoate, was discovered by gas chromatography-coupled electroantennogram detection (GC-EAD), and identified by gas chromatography–mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR). The synthesis yielded an 86:14 mixture of methyl (E)-3-(2-hydroxyethyl)-4-methyl-2-pentenoate (active) and methyl (Z)-3-(2-hydroxyethyl)-4-methyl-2-pentenoate (inactive), along with a lactone breakdown product. The activity of the synthetic E-isomer was confirmed by GC-EAD, GC-MS, NMR, and bioassays. No antennal response was observed to the Z-isomer or the lactone. In a two-choice olfactometer bioassay, female D. abbreviatus moved upwind towards the synthetic pheromone or natural pheromone more often compared with clean air. Males showed no clear preference for the synthetic pheromone. This pheromone, alone or in combination with plant volatiles, may play a role in the location of males by female D. abbreviatus

Multimodal Stimulation of Colorado Potato Beetle Reveals Modulation of Pheromone Response by Yellow Light

Orientation of insects to host plants and conspecifics is the result of detection and integration of chemical and physical cues present in the environment. Sensory organs have evolved to be sensitive to important signals, providing neural input for higher order multimodal processing and behavioral output. Here we report experiments to determine decisions made by Colorado potato beetle (CPB), Leptinotarsa decemlineata, in response to isolated stimuli and multimodal combinations of signals on a locomotion compensator. Our results show that in complete darkness and in the absence of other stimuli, pheromonal stimulation increases attraction behavior of CPB as measured in oriented displacement and walking speed. However, orientation to the pheromone is abolished when presented with the alternative stimulation of a low intensity yellow light in a dark environment. The ability of the pheromone to stimulate these diurnal beetles in the dark in the absence of other stimuli is an unexpected but interesting observation. The predominance of the phototactic response over that to pheromone when low intensity lights were offered as choices seems to confirm the diurnal nature of the insect. The biological significance of the response to pheromone in the dark is unclear. The phototactic response will play a key role in elucidating multimodal stimulation in the host-finding process of CPB, and perhaps other insects. Such information might be exploited in the design of applications to attract and trap CPB for survey or control purposes and other insect pests using similar orientation mechanisms

Morphometric Analysis of the Host Effect on Phenotypical Variation of Belminus ferroae

The Triatominae subfamily includes hematophagous insects, well known for their role as vectors for the Trypanosoma cruzi parasite, etiologic agent of Chagas’ disease. Belminus ferroae is a triatomine that showed an increased demographic fitness when cockroaches were used as hosts. Here we compare the centroid size (CS) and wing shape between B. ferroae parents and three successive generations (O1, O2, and O3) of their offspring fed on cockroaches or mice under laboratory conditions. Morphometric analysis of the wings bugs fed on cockroaches showed a significant reduction in CS in both sexes among all generations. Sexual size dimorphism (SSD) was observed in the insects fed on cockroaches (O2 and O3), as well as those bugs fed on mice (O2). Differences in the shape of wings were observed between parental and offspring wings when fed on mice, but not in males (O1, O2, and O3) or females (O1 and O2) fed on cockroaches. There was a greater wing shape similarity between the cockroach-fed offspring and their parents according to the Mahalanobis distances. Our results support the idea of higher adaptation of this Triatominae with arthropod hosts