Thermoregulatory behavior of lekking male desert locusts, Schistocerca gregaria, in the Sahara Desert.

Most terrestrial animals are constrained by extreme heat conditions such as midday desert environments, while a few terrestrial ectothermic insects are active in such ecological niches. Sexually mature males of the desert locust (Schistocerca gregaria) in the Sahara Desert remain on the open ground, despite the ground temperatures exceeding their lethal limit, to form leks and to mate incoming gravid females during the daytime. Lekking male locusts apparently suffer from extreme heat stress and greatly fluctuating thermal conditions. The present study examined the thermoregulatory strategies of the lekking male S. gregaria. Our field observations showed that lekking males changed their body orientation toward the sun depending on the temperature and time of day. In the relatively cool morning, males basked by orienting perpendicular to the sun's rays, maximizing the area of body surface exposed to the sun's rays. In contrast, around midday, when the ground surface temperature exceeded lethal high temperatures, some males tended to shelter inside the plants or remain in the shade. However, the remainder stayed on the ground, stilted (i.e., extending their legs to raise their bodies off the hot ground) and oriented parallel to the sun's rays, which minimized radiative heating. Measurements of body temperature throughout the hot middle period of the day confirmed that the stilting posture prevented overheating. Their critical lethal body temperature was as high as 54.7 °C. In this lekking system, gravid females enter male leks by flying. These incoming females usually landed on open ground, whereupon nearby males immediately approached, mounted, and mated the female, implying that males with greater heat-tolerance can increase mating chance. These results suggest that behavioral thermoregulation and physiologically high heat tolerance of male desert locusts allows them to endure extreme thermal conditions for lekking.

Neoformación condilar posterior a una reconstrucción mandibular con colgajo libre microvascularizado de peroné: un informe de caso / Condylar neoformation after mandibular reconstruction with microvascularized fibula free flap: a case report

El colgajo microvascularizado de peroné es el estándar de oro para la reconstrucción mandibular por su gran capacidad de remodelación ósea; se ha evidenciado que el segmento distal del peroné puede tomar la forma y estructura de un cóndilo. Se reporta el caso clínico de un paciente adulto de sexo masculino diagnosticado con mixoma odontogénico, quien fue intervenido quirúrgicamente a través de una hemimandibulectomía con resección total del cóndilo y una reconstrucción mandibular primaria mediante un colgajo libre microvascularizado de peroné. Después de 30 meses de seguimiento se observó una neoformación condilar y adaptación progresiva a la cavidad glenoidea, a pesar de que el extremo distal del peroné se encontró originalmente alejado de la posición planificada de manera digital. (AU)

The microvascularized fibula flap is the gold standard for mandibular reconstruction due to its great capacity for bone remodelling, it has been shown that the distal segment of the fibula can take on the shape and structure of a condyle. We report the clinical case of an adult male patient diagnosed with odontogenic myxoma, who was underwent hemimandibulectomy with total resection of the condyle and primary mandibular reconstruction using a microvascularized free flap of the fibula. After 30 months of follow-up, condylar neoformation and progressive adaptation to the glenoid cavity was observed even though the distal end of the fibula was originally distant from the digitally planned position. (AU)

A Novel Prototype for Safe Driving Using Embedded Smart Box System.

Every day, vehicle accidents occur and many of them might be avoided if the drivers demonstrated excellent driving without mistakes. This paper presents a novel prototype applied in a real transportation system, particularly for buses, to avoid accidents, which may involve numerous victims, and even occasionally cause death. This system consists of a wearable device and embedded system with several sensors connected via Bluetooth, similar to the Internet of Things (IoT). Wearable devices are made to monitor the driver's heart rate and alert the driver if they are in a state of sleep deprivation to prevent any potential accidents. The embedded system includes a Global Positioning System (GPS), accelerometers, and gyroscopes attached to a Smart Box mounted on the bus. The embedded system alert function will be triggered if an accident occurs and automatically sends the geolocation of the accident to the registered phone number through a message using a mobile phone. The results for all scenarios were significant when measured by an automatic accident trigger via the smart box if the value of measured values in each axis exceeded 583. In conclusion, the implementation of this innovative solution at the system-level was shown to be satisfactory in terms of the safety mechanism used by the nominated drivers.

Density-dependent mating behaviors reduce male mating harassment in locusts.

Male mating harassment may occur when females and males do not have the same mating objectives. Communal animals need to manage the costs of male mating harassment. Here, we demonstrate how desert locusts in dense populations reduce such conflicts through behaviors. In transient populations (of solitarious morphology but gregarious behavior), we found that nongravid females occupied separate sites far from males and were not mating, whereas males aggregated on open ground (leks), waiting for gravid females to enter the lekking sites. Once a male mounted a gravid female, no other males attacked the pair; mating pairs were thereby protected during the vulnerable time of oviposition. In comparison, solitarious locusts displayed a balanced sex ratio in low-density populations, and females mated irrespective of their ovarian state. Our results indicate that the mating behaviors of desert locusts are density dependent and that sex-biased behavioral group separation may minimize the costs of male mating harassment and competition.

A general model of the thermal constraints on the world's most destructive locust, Schistocerca gregaria.

All terrestrial ectotherms are constrained to some degree by their thermal environment and the extent to which they can behaviorally buffer variable thermal conditions. New biophysical modeling methods (NicheMapR) allow the calculation of the body temperature of thermoregulating animals anywhere in the world from first principles, but require detailed observational data for parameterization and testing. Here we describe the thermoregulatory biology of marching bands of the desert locust, Schistocerca gregaria, in the Sahara Desert of Mauritania where extreme heat and strong diurnal fluctuations are a major constraint on activity and physiological processes. Using a thermal infrared camera in the field, we showed that gregarious nymphs altered the microhabitats they used, as well as postural thermoregulatory behaviors, to maintain relatively high body temperature (nearly 40°C). Field and laboratory experiments demonstrated that the preferred body temperature accelerated digestive rates. Migratory bands frequently left foraging sites with full guts before consuming all vegetation and moved to another habitat before emptying their foregut. Thus, the repertoire for behavioral thermoregulation in the desert locust strongly facilitates foraging and digestion rates, which may accelerate developmental rates and increase survival. We used our data to successfully parameterize a general biophysical model of thermoregulatory behavior that could capture hourly body temperature and activity at our remote site using globally available environmental forcing data. This modeling approach provides a stronger basis for forecasting thermal constraints on locust outbreaks under current and future climates.

Daily microhabitat shifting of solitarious-phase Desert locust adults: implications for meaningful population monitoring.

The Desert locust Schistocerca gregaria is a major world pest that causes substantial agricultural and economic damage. Effective pest control relies on effective monitoring, which requires knowledge of locust microhabitat selection. Yet little is known about microhabitat selection of solitarious adult locusts in the field. We conducted field surveys to investigate fine-scale diel temporal and spatial distributions of solitarious adults in the Sahara Desert in Mauritania, a major breeding and recession area. We found that solitarious adults moved among different, specific microhabitats throughout the 24-h period in a cyclical manner. At night, they roosted in trees, moved to the ground to feed shortly after dawn, sheltered in low vegetation during the hot midday, and returned to the ground in the late afternoon. Hence, they switched microhabitats and plant species throughout each day. These cyclical daily movements among diverse microhabitats and specific plant species were correlated with time of day, light intensity, temperature, humidity, and specific plant species, and may relate to anti-predator defence, thermoregulation, and feeding. The present study suggests that locust monitoring should be adjusted, based on time of day, locust age, phase state and relative abundance of specific plant species. For example, we recommend surveying ground after morning and trees at night, for solitarious adults, when at low density.

Distribution, host preference and infection rates of malaria vectors in Mauritania.

This study reports for the first time on the distribution, host preference and infection rates of malaria vectors in Mauritania. It was conducted during an outbreak of Rift valley fever. Three anopheline species were reported. An. arabiensis was the predominant species observed in all regions whereas An. pharoensis and An. funestus were observed along the south border in the Senegal River valley where extensive irrigation schemes are present. The distribution limits of anopheline species were observed from the Senegal River basin in the Trarza region up to the south limit of the Saharan desert in Tidjikja city. Overall, all An. funestus and An. pharoensis were fed respectively on human and ovine hosts whereas the mean anthropophilic rate of An. gambiae s.l. was 53%. A low Plasmodium falciparum infection rate was observed for species of the An. gambiae complex (0.17%) represented mainly by An. arabiensis. Because of the specific nature of this investigation, longitudinal studies are essential to better characterize the malaria vectors and their respective role in malaria transmission.

Rift Valley fever outbreak with East-Central African virus lineage in Mauritania, 2003.

In October 2003, 9 human cases of hemorrhagic fever were reported in 3 provinces of Mauritania, West Africa. Test results showed acute Rift Valley fever virus (RVFV) infection, and a field investigation found recent circulation of RVFV with a prevalence rate of 25.5% (25/98) and 4 deaths among the 25 laboratory-confirmed case-patients. Immunoglobulin M against RVFV was found in 46% (25/54) of domestic animals. RVFV was also isolated from the mosquito species Culex poicilipes. Genetic comparison of virion segments indicated little variation among the strains isolated. However, phylogenetic studies clearly demonstrated that these strains belonged to the East-Central African lineage for all segments. To our knowledge, this is the first time viruses of this lineage have been observed in an outbreak in West Africa. Whether these strains were introduced or are endemic in West Africa remains to be determined.