Soil compaction is an important degradation phenomenon that can affect root growth, and consequently crop yield. Therefore it becomes relevant to have soil compaction data for future improvements on precision agriculture management. A traditional on-the-field data related to soil compaction is cone index obtained using a penetrometer; however, this methodology is time consuming for a high density data. Therefore, on-the-go sensors have been developed to continually estimate the variable of interest. This work proposes an on-the-go sensor to estimate the soil horizontal resistance at different depths. The main design concept is based on embedded load cells at three different depths, resulting in a robust sensor with high sensitivity. The prototype was first tested and calibrated in laboratory, and then, it was tested in the field. The calculated horizontal resistance index (HRI) at the three depths was correlated with the cone index (CI) using a cone penetrometer, showing that this sensor can replace the penetrometer data, allowing the possibility of taking continuous data on the field.

La compactación de los suelos agrícolas es un fenómeno que afecta el normal desarrollo de las raíces de los cultivos y consecuentemente su posterior rendimiento. Por lo tanto, disponer de la información del estado de compactación del suelo será relevante en un futuro en lo que respecta a la agricultura de precisión. La información usual recolectada en campo relacionada con la compactación del suelo es el índice de cono (CI), obtenido mediante el uso del penetrómetro. Sin embargo, la obtención de dicha información con una alta resolución espacial a partir del penetrómetro resulta ineficiente y altamente costosa. Atendiendo a esta dificultad, se han desarrollado sensores on-the-go, cuya principal característica es su capacidad de registrar de manera continua la resistencia mecánica del suelo, con una alta resolución espacial tanto en el plano horizontal como en el vertical. Dicha característica reduce de manera significativa los tiempos y los costos de adquisición de la información de la resistencia mecánica del suelo, por la cual a partir de la misma se estima el estado de compactación del suelo. En este trabajo se presenta un sensor para medir de forma continua la resistencia mecánica del suelo en tres profundidades diferentes del suelo. En este dispositivo se utilizan celdas de cargas embebidas en el propio seno de dicho sensor promoviendo así un desempeño robusto y con una alta sensibilidad. El prototipo de este sensor fue en primera instancia evaluado y calibrado en laboratorio, para luego finalmente evaluar su desempeño en pruebas a campo. La resistencia mecánica horizontal del suelo en los tres intervalos de profundidad relevados por dicho sensor ha sido correlacionada con el índice de cono (CI) obtenido mediante un penetrómetro, mostrando que resulta factible la utilización de la información relevada por este sensor en la estimación del estado de compactación del suelo.

Many arthropod species have adopted vertebrate blood as their main food source. Blood is rich in nutrients and, except for the presence of parasites, sterile. However, this food source is not freely available, nor is obtaining it devoid of risk. It circulates inside vessels hidden underneath the skin of mobile hosts that are able to defend themselves and even predate the insects that try to feed on them. Thus, the haematophagous lifestyle is associated with major morphological, physiological and behavioural adaptations that have accumulated throughout the evolutionary history of the various lineages of blood-sucking arthropods. These adaptations have significant consequences for the evolution of parasites as well as for the epidemiology of vector-transmitted diseases. In this review article, we analyse various aspects of the behaviour of triatomine bugs to illustrate how each behavioural trait represents a particular adaptation to their close association with their hosts, which may easily turn into predators. Our aim is to offer to the reader an up-to-date integrative perspective on the behaviour of Chagas disease vectors and to propose new research avenues to encourage both young and experienced colleagues to explore this aspect of triatomine biology.

Triatomines have been important model organisms for behavioural research. Diverse reports about triatomine host search, pheromone communication in the sexual, shelter and alarm contexts, daily cycles of activity, refuge choice and behavioural plasticity have been published in the last two decades. In recent times, a variety of molecular genetics techniques has allowed researchers to investigate elaborate and complex questions about the genetic bases of the physiology of insects. This, together with the current characterisation of the genome sequence of Rhodnius prolixus allows the resurgence of this excellent insect physiology model in the omics era. In the present revision, we suggest that studying the molecular basis of behaviour and sensory ecology in triatomines will promote a deeper understanding of fundamental aspects of insect and, particularly, vector biology. This will allow uncovering unknown features of essential insect physiology questions for a hemimetabolous model organism, promoting more robust comparative studies of insect sensory function and cognition.

The factors affecting the sexual behaviour of Panstrongylus megistus were studied under laboratory conditions. A general description of mating behaviour is presented for this species. The effect of the time elapsed after the first imaginal feeding on the mating frequency, the motivation of males to mate and the rejection behaviour by females, were analyzed. We also determined the number of copulas accepted by females of this species. Finally, the possible existence of a sexual chemical signal promoting male aggregation around mating couples was evaluated. Results showed that mating frequency increased with the time elapsed since the first adult meal. Despite the number of male copulatory attempts did not change as a function of time, the rejection behaviour of females became gradually less frequent. Females rejected mating by means of body flattening on the substrate, abdominal movements, evasion or stridulation. After a single copula, females did not usually accept to mate again. Neither male nor female aggregation around mating couples was observed, suggesting the absence of a sexual assembling pheromone in P. megistus.