Host selection of hematophagous leeches (Haemadipsa japonica): Implications for iDNA studies

The development of an efficient and cost‐effective method for monitoring animal populations or biodiversity is urgently needed, and invertebrate‐derived DNA (iDNA) may offer a promising tool for assessing the diversity and other ecological information of vertebrates. We studied the host species of a hematophagous leech (Haemadipsa japonica) in Yakushima by genetic barcoding and compared the results with those for mammal composition revealed by camera trapping. We analyzed 119 samples using two sets of primers by Sanger sequencing and one set of primer by next generation sequencing. The proportion of the samples that were successfully sequenced and identified to at least one species was 11.8–24.3%, depending on the three different methods. In all of these three methods, most of the samples were identified as sika deer (18/20, 6/15 and 16/29) or human (2/20, 7/15 and 21/29). The nonhuman mammal host species composition was significantly different from that estimated by camera trapping. Sika deer was the main host, which may be related with their high abundance, large body size and terrestriality. Ten samples included DNA derived from multiple species of vertebrates. This may be due to the contamination of human DNA, but we also found DNA from deer, Japanese macaque and a frog in the same samples, suggesting the mixture of the two meals in the gut of the leech. Using H. japonica‐derived iDNA would not be suitable to make an inventory of species, but it may be useful to collect genetic information on the targeted species, due to their high host selectivity

Activity of wild Japanese macaques in Yakushima revealed by camera trapping: Patterns with respect to season, daily period and rainfall

Animals are subject to various scales of temporal environmental fluctuations, among which daily and seasonal variations are two of the most widespread and significant ones. Many biotic and abiotic factors change temporally, and climatic factors are particularly important because they directly affect the cost of thermoregulation. The purpose of the present study was to determine the activity patterns of wild Japanese macaques (Macaca fuscata) with a special emphasis on the effect of thermal conditions. We set 30 camera traps in the coniferous forest of Yakushima and monitored them for a total of 8658 camera-days between July 2014 and July 2015. Over the one-year period, temperature had a positive effect, and rainfall had a negative effect on the activity of macaques during the day. Capture rate was significantly higher during the time period of one hour after sunrise and during midday. During winter days, macaques concentrated their activity around noon, and activity shifted from the morning toward the afternoon. This could be interpreted as macaques shifting their activity to warmer time periods within a single day. Japanese macaques decreased their activity during the time before sunrise in seasons with lower temperatures. It was beneficial for macaques to be less active during cooler time periods in a cold season. Even small amounts of rainfall negatively affected the activity of Japanese macaques, with capture rates decreasing significantly even when rainfall was only 0.5–1 mm/min. In conclusion, thermal conditions significantly affected the activity of wild Japanese macaques at various time scales

Capture rate of Japanese macaques in the six daily time periods.

<p>Significant differences among the time periods (indicated by χ² tests with Bonferroni corrections) are indicated by different lowercase letters in the order a</p

Daily activity patterns of Japanese macaques.

<p>Y axis and the curves are the kernel density estimates of the filming events. Light gray areas represent one hour before sunrise and one hour after sunset, and dark gray areas represent nighttime; note that the widths of these areas vary among seasons due to the fluctuating time of sunrise and sunset. (a) All seasons combined, (b) summer (July, August and September), (c) fall (October and November), (d) winter (December, January, February and March), and (e) spring (April, May and June).</p

The location of Yakushima, the study area in Yakushima and the camera trapping sites.

<p>Contours were drawn every 300 m in the map of Yakushima. The map of the study sites was drawn based on a map provided by the Geospatial Information Authority of Japan.</p

Dates and times when the videos of Japanese macaques were taken (triangle).

<p>Circles indicate the time of sunrise and sunset.</p

Activity of wild Japanese macaques in Yakushima revealed by camera trapping: Patterns with respect to season, daily period and rainfall - Fig 5

<p>Examples of the movies of Japanese macaques taken by camera trapping in daytime (a and b) and nighttime (c and d). Still images were taken from the movies filmed at (a)17:01 on February 2015, (b)12:01 on August 5, 2014, (c) 1:30 on November 12, 2014, and (d) 18:30 on November 7, 2014.</p