Benefits and Costs of Mixed-Species Aggregations in Harvestmen (Arachnida: Opiliones)

Many animals form aggregations with individuals of the same species (single-species aggregations, SSA). Less frequently, individuals may also aggregate with individuals of other species (mixed-species aggregations, MSA). Although the benefits and costs of SSA have been intensively studied, the same is not true for MSA. Here, we first review the cases of MSA in harvestmen, an arachnid order in which the records of MSA are more frequent than other arthropod orders. We then propose several benefits and costs of MSA in harvestmen, and contrast them with those of SSA. Second, using field-gathered data we describe gregariousness in seven species of Prionostemma harvestmen from Costa Rica. These species form MSA, but individuals are also found solitarily or in SSA. We tested one possible benefit and one possible cost of gregariousness in Prionostemma harvestmen. Regarding the benefit, we hypothesized that individuals missing legs would be more exposed to predation than eight-legged individuals and thus they should be found preferentially in aggregations, where they would be more protected from predators. Our data, however, do not support this hypothesis. Regarding the cost, we hypothesized that gregariousness increases the chances of parasitism. We found no support for this hypothesis either because both mite prevalence and infestation intensity did not differ between solitary or aggregated individuals. Additionally, the type of aggregation (SSA or MSA) was not associated with the benefit or the cost we explored. This lack of effect may be explained by the fluid membership of the aggregations, as we found high turnover over time in the number of individuals and species composition of the aggregations. In conclusion, we hope our review and empirical data stimulate further studies on MSA, which remains one of the most elusive forms of group living in animals.

Component Endoparasite Communities Mirror Life-History Specialization in Syntopic Reed Frogs (Hyperolius spp.)

Most of our knowledge on the processes structuring parasite communities in amphibians originate from temperate-zone taxa, whereas Afrotropical communities have been neglected so far. We found evidence that ecological fitting of the hosts and, probably, differential immune response may influence the variation in parasite species richness, prevalence, and infestation intensity of East African frogs Hyperolius kivuensis and H. viridiflavus. The most closely related host species share the same macrohabitat (that implies the same pool of potential parasites), but differ in microhabitat preference, so that a comparative analyses of syntopic and allopatric populations is expedient to reveal ecological fitting. We detected 11 parasite species (one annelid, four nematodes, five trematodes, one cestode) and two endocommensal species (protozoans). The component parasite communities included 4–5 helminth species in H. kivuensis and 6–8 in the more aquatic H. viridiflavus, supporting the hypothesis that trematode diversity increases with the amount of time spent in water. Five parasite species (Orneoascaris chrysanthemoides, Clinostomum chabaudi, an undetermined echinostomatid) and two protozoans (Nyctotheroides sp., and Protoopalina sp.) are shared among the syntopic amphibian populations. This finding indicates a similar susceptibility of these amphibians to infestation from the local parasite pool. Yet, the low prevalence of single- and multi-species infestations in H. kivuensis indicates that parasite clearing by its immune response is probably more effective and prominent than in H. viridiflavus. Therefore, H. viridiflavus suffered from significantly reduced short-term survival due to the infection. Thus, we conclude that the processes structuring component parasite communities in amphibians do not differ generally between temperate-zone and Afrotropical host species, but they do in the magnitude of ecological fitting.

Effects of Epibiotic Diatoms on the Productivity of the Calanoid Copepod Acartia tonsa (Dana) in Intensive Aquaculture Systems

We evaluated here the effects of the epibiotic diatom Tabularia sp. on the productivity of the calanoid copepod Acartia tonsa (Dana) for assessing their risk on copepod intensive aquaculture industry for the provision of live feed. In the first experiment, uninfested and intensively infested females were cultivated individually for the assessment of egg production. Intensively infested females appeared to have a significantly lower egg production (5.0–9.0 eggs/female/d) than uninfested females (22.0–26.0 eggs/female/d) during 5 consecutive days. In the second experiment, effects of culture densities on diatom epibiosis were investigated in 9 L cultures at three different densities (200, 400, and 600 ind. L–1). Another culture at higher volume (250 L) and lowest density (200 ind. L–1) was also carried out to test the effect of culture volume on diatom epibiosis. The infestation rate (%), infestation intensity (ratio of surface diatom coverage levels, classified as levels 0–3) and daily egg harvest rate (number of harvested eggs per day per liter) were evaluated among the four culture populations. The copepods had higher infestation rate (53.69–60.14%) and intensity rate (high ratios at level 2 and 3) when the densities were increased from 200 ind./L to 400 and 600 ind./L. Although egg harvest increased with increasing culture density, it seemed that the diatom-infested A. tonsa population reach a saturated egg production when the density was higher than 400 ind./L. Nevertheless, the differences of culture volumes (250 and 9 L) appeared to be not to have any effect when the copepods were cultivated at the same density (200 ind./L). This study reveals for the first time that the epibiosis of the diatom Tabularia sp. reduces the individual egg production, and egg harvest rate in high-density culture of the copepod A. tonsa. Our findings implicate that diatom epibiosis should be avoid in copepod intensive culture systems.

Tick (Acari: Ixodidae) infestation of cuscuses from Maluku Province, Indonesia

Background and Aim: Cuscuses are one of the endemic Indonesian marsupials, which needs to be protected and revived in terms of the numbers and range of species. Ectoparasites of ticks (Ixodidae) are one potential obstacle to cuscus conservation. Tick infestation can cause blood loss in the host, even being a predisposing factor for infection with pathogenic organisms. This study aimed to determine the prevalence, infestation intensity, and species of ticks present on cuscuses in Maluku Province, Indonesia. Materials and Methods: Ticks were collected from cuscuses origin of the four regions in Maluku Province, namely the island of Ambon, Seram Island, Romang Island, and Wetar Island . Cuscuses were captured at night, with ticks being collected from them from the head to the tip of the tail. The tick samples obtained from the cuscuses were preserved, identified, and counted. Cuscuses were released back into their habitat after collecting the ticks. The obtained ticks were observed using an Olympus BX51 microscope with an Olympus DP12 digital camera and prepared for examination under a scanning electron microscope (SEM). Infestation rate, infestation intensity, and morphology of the species were described. Results: The cuscuses were found to be infested with Ixodes cordifer ticks. Cuscuses in Maluku Province had a low tick infestation rate. The range of infestation prevalence of island origin cuscuses in Maluku was between 14.28% and 16.67%. Simultaneously, I. cordifer infestation level was mildly infested based on the intensity of thick infestation ranged from 1 to 1.2 ticks per cuscus. From observation of the tick surface structure under SEM, sexual dimorphism and various specific characteristics of the ticks were identified. Conclusion: The low infestation rate of I. cordifer ticks in cuscus was influenced by the up and down movement of the conscious activity in the tree, which allowed minimal contact with the ticks. The infestation prevalence rates on each island studied were similar. Such similarities of infestation are related to the similarity of cuscus species among Ambon, Lakor, Seram, and Romang islands, which are all included in the Phalangeridae family, and their similar habitats, behaviors, climatic conditions, and geographical areas.

TINGKAT SERANGAN LALAT BUAH DAN THRIPS PADA CABAI DENGAN BERBAGAI TEKNIK PENGENDALIAN HAMA DAN PENYAKIT

Microbe-intensive technology is an integrated package of various biocontrol agents in chili cultivation. This technology was known to be effective in suppressing various chili diseases. The effect of this technique on the two mayor pests of chili, i.e. fruit flies (Bactrocera sp) and thrips (Thrips sp) is still unknown. The aim of this study was to find out the effect of microbeintensive technology on the infestation intensity of fruit flies and thrips on chili pepper. The study consisted of four treatments, namely fully microbe- intensive, microbe- intensive in the nursery, conventional, and control. The research was conducted in three locations with different altitudes. Infestation intensity of fruit fly were observed at 10 and 11 weeks after planting, while observations of infestation intensity of thrips were carried out once a week from 2 to 10 weeks after planting. The application of microbe-intensive technology significantly reduced the infestation rate of fruit flies. Microbe-intensive technology reduced thrips infestation at two planting locations, i.e. Margasari and Bojong, but It was not significantly affect the thrips infestation on Bumijawa.

Evaluation of the Efficacy of Chemical Insecticides and Biopesticides against Flea Beetle in Cabbage (Brassica oleracea var. Capitata)

Aims: This study aimed to evaluate chemical insecticides and bio-pesticides against flea beetle in cabbage. Study Design: The experiment was laid out at a randomized complete block design with three replications. Place and Duration of Study: Experimental farm of Sher-e-Bangla Agricultural University, Bangladesh during the period from October 2017 to March 2018. Methodology: The experiment consisted of nine treatments viz. T1(Sevin 85 WP @ 2g/L of water), T2 (Decis 2.5 EC @ 1.0 ml/L of water), T3 (Voliam flexi @ 0.5 ml/L of water), T4 (Ripcord 10 EC @ 1.0 ml/L of water), T5 (Dursban 20EC @ 1 ml L-1 of water), T6 (Tobacco leaf extract @ 3 g L-1 of water), T7 (Neem seed kernel extract @ 3 g L-1 of water), T8 (Bioneem plus 1 EC @ 1 ml L-1 of water) and T9 (Untreated Control) were used at 7 days interval. Results: Stripped flea beetle(Phyllotreta striolata) and white-spotted flea beetle (Monolepta signata), these two species of flea beetle were found in the experimental field. Among all the treatments T4 (Ripcord 10EC)performed the best in managing flea beetles based on the lowest percentage of leaf infestation (5.84%), lowest no. of holes per plant (6.13), lowest percentage of head infestation by number (18.04) and highest percentage of infestation reduction over control on all parameters at vegetative stage of plant. Again, the lowest leaf infestation intensity (5.73%), lowest number of holes per infested head (14.00), lowest percentage of infestation of head by number (6.69) were achieved at harvesting stage from the same treatment (T4) whereas the highest values of all these parameters were achieved from untreated control treatment (T9). T4 treatment provided the best performance in yield where yield was increased (112.51 %) over control, giving maximum yield 75.76 tons ha-1. Bioneem plus 1 EC (T8) performed the best among the biopesticides while the neem seed kernel extract showed less effectivity against flea beetle. Conclusion: It is concluded that in case of chemical insecticides Ripcord 10EC while in case of biopesticides Bioneem plus 1 EC would be effective for flea beetle management.

Effect of seasonality and microclimate on the variation in bat-fly load (Diptera: Streblidae) in a cave bat assemblage in a dry forest

Seasonality causes fluctuations in the availability of resources, affecting the presence and abundance of animal species. These fluctuations can have an impact on parasite-host relationships, which in turn can be exacerbated by microclimatic changes to which bat-flies are exposed. We characterized the bat-fly load and evaluated the effect of seasonality on five bat species in a dry forest. We evaluated variations in microclimatic conditions inside the cave Cerro Huatulco between seasons and the response of the bat-fly load. We collected 1165 bat-fly specimens belonging to 16 species from 688 bats. The obtained results indicate that the mean abundance and infestation intensity exhibited changes between seasons in Artibeus jamaicensis, Desmodus rotundus, Glossophaga soricina, and Pteronotus parnellii. In the case of the effect of microclimate conditions, we observed that prevalence is negatively correlated with temperature in G. soricina, while mean abundance and mean infestation intensity were negatively related to temperature in A. jamaicensis and G. soricina. The present study provides significant information about host-parasite relationships in a dry forest and discusses the relevance of abiotic and biotic factors that could affect host-parasite interactions, as well as the importance of each parasite load parameter for the understanding of this interaction.

Phenology and phylogeny of Hyalomma spp. ticks infesting one-humped camels (Camelus dromedarius) in the Tunisian Saharan bioclimatic zone

In this study, we report the results of a survey of Hyalomma ticks infesting one-humped camels in southern Tunisia. Examinations were conducted every second or third month on 406 camels in Tataouine district from April 2018 to October 2019. A total of 1902 ticks belonging to the genus Hyalomma were collected. The ticks were identified as adult H. impeltatum (41.1%; n = 782), H. dromedarii (32.9%; n = 626), H. excavatum (25.9%; n = 493), and H. marginatum for a single specimen. Although the camels were infested by ticks throughout the year, the highest overall infestation prevalence was observed in April 2018 (p < 0.01). The overall infestation intensity varied between 2.7 and 7.4 ticks/animal. There were no statistically significant differences in tick infestation prevalence based on age categories of the camels, and the overall infestation prevalence was between 82.7% and 97.4%. Female camels were significantly more infested with ticks (88.3%) than males (65.5%) (p < 0.01). The infestation prevalence of camels varied significantly according to the region where sampling took place (p < 0.01), but no correlations were found with abiotic factors. The preferred attachment sites for adult Hyalomma ticks were the sternum (38.3%; n = 729/1902), around the anus (36.2%; n = 689/1902), udder (18.4%; n = 350/1902), and inner thigh (6.9%; n = 132/1902). Morphological classification of ticks was corroborated by sequencing the cytochrome c oxidase I (Cox1) and 16S rDNA genes, and these sequences were also used to infer phylogenetic relationships. A single H. dromedarii seemed to be a natural hybrid with H. rufipes. More attention should be devoted by the veterinary services to the infestation of camels by ticks.

Helminthofauna of ruminants and solipeds in the Center for Breeding Steppe Animals “Orenburg Tarpaniya”

During the autumn-winter-spring season of 2016-2017, the Center for Breeding Steppe Animals (Orenburg region) conducted coprological surveys of herbivores. Identified contamination strongylata have yaks and camels at a low infestation intensity. These animals were not dehelmintizated in the autumn period. By spring, the strongylate infestation intensity in camels increased. The kiangs and Przewalski’s horses kept here were subjected to autumn dehelmintization. In these animals, helminths were not detected during the entire study period. It is recommended to carry out planned dehelmintization of animals kept in small protected areas.

Species diversity, abundance and damaged caused by rats in oil palm plantation in West and Central Sulawesi, Indonesia

Ikhsan M, Priyambodo S, Nurmansyah A, Hendarjanti H, Sahari B. 2020. Species diversity, abundance and damaged caused by rats in oil palm plantation in West and Central Sulawesi, Indonesia. Biodiversitas 21: 5632-5639. Oil palm is one of the plantation commodities which has an important role in Indonesia’s economy. Indonesia is the largest producer and exporter of oil palm in the world with its export value capable of supplying 55.78% of global consumption. Rats are wild animals that are important pests for human life, both in agriculture plantations and urban areas. Rats can damage crops at various stages of plant growth. This study was aimed to determine the species abundance of rats in oil palm plantations, calculate the severity of crop damage due to rats infestation. Three blocks of mature plants were used in OC and OH plantation blocks were used to calculated, crop damage caused by rats, Identify the species of rats, and estimated rats abundance. The results of these studies showed there were four species of rats found in the oil palm plantation, namely Rattus tiomanicus, R. tanezumi, Rattus sp, and Maxomys hellwaldii. However, only R. tiomanicus and R. tanezumi were dominant species. There were significant differences in the number of, sex, and body weight between R. tiomanicus and R. tanezumi. The OC 12 block had the lowest infestation intensity than the other blocks since it was well maintained. The OH 02 block had the highest infestation intensity, infestation area, and abundance due to a lack of maintenance.