Activity Recording of Free-Ranging Tri-spine Horseshoe Crabs in the Southeastern Coast of Sabah,Borneo

In Inderasabah(southeast Sabah),tri-spine horseshoe crab Tachypleus tridentatus was observed for their locomotion activity using data loggers from September to November in 2015.A female with acceleration and depth-temperature loggers and five males with acceleration loggers were recaptured between 10 and 49 days after their release.From the record of 194 activity days that involve all six T.tridentatus,four horseshoe crabs,including the female,were active throughout the 24.0 h cycle,whereas the activity of the remaining two males was consistent with the 12.4 h cycle.Using the 40-day recording,three horseshoe crabs,including the female,were primarily active around the new moon and full moon,but they were dormant around the first and third quarter moon days.The female spent much time in shallow shores(depth<0.3 m)during the new moon and full moon.This result indicated that the female attempted to spawn in a minimum of three spring tide periods while lingering in the vicinity.Meanwhile,after spawning,the female spent time foraging in shallow water(depth 0.3–18 m).As for the two male individuals,their activity was consistent with semi-lunar periodicity.Therefore,both of them were in amplexus.In addition,a solitary male individual was active only during the first and third quarter moon days.Through activity recording,all the T.tridentatus in Inderasabah was active during daytime and nighttime.This result was contrary to T.tridentatus activity cycles in western Japan,where the species was found to be primarily nocturnal.Perhaps,the regional differences in activity cycles for T.tridentatus were related to their population adaptation toward water temperature,depth,and prey-searching periods.

Changes in soil faunal density and microbial community under altered litter input in forests and grasslands

Root and foliar litter inputs are the primary sources of carbon and nutrients for soil fauna and microorganisms,yet we still lack a quantitative assessment to evaluate the effects of root and foliar litter on various groups of soil organisms across terrestrial ecosystems.Here,we compiled 978 paired observations from 68 experimental sites to assess the directions and magnitudes of adding and removing foliar and root litter on the soil faunal density and microbial biomass that was evaluated by phospholipid fatty acids(PLFAs)across forests and grasslands worldwide.We found that litter addition had only a marginal effect on soil faunal density but significantly increased the soil total microbial-,fungal-and bacterial-PLFAs by 13%,14%,and 10%,respectively,across ecosystems,suggesting that the soil microbial community is more sensitive to carbon source addition than soil fauna,particularly in soils with low carbon to nitrogen ratios.In contrast,removing litter significantly decreased the soil faunal density by 17%but had few effects on soil microorganisms.Compared with foliar litter,root litter input had a more positive effect on the development of soil fungal taxa.The effect of both litter addition and removal on soil faunal density and microbial biomass did not differ between humid and arid regions,but a greater influence was observed in grasslands than in forests for soil microbial community.Our results highlight that the increasing litter production under a global greening scenario would stimulate microbial activity in grasslands more than in forests,and this stimulation would be greater for soil microbes than soil fauna.