02475nas a2200205   4500008004100000245009900041210006900140260001200209300001000221490000700231520185000238653002402088653001202112653001302124653002702137653001602164100002302180700002302203856004302226       2011                        eng d00aSynchronized Circadian Bioluminescence in Cave-Dwelling Arachnocampa tasmaniensis (Glowworms) 0 aSynchronized Circadian Bioluminescence in CaveDwelling Arachnoca  c02/2011  a34-430 v263 aLarvae of the genus Arachnocampa, known as glowworms, are bioluminescent predatory insects that use light to attract prey. One species, Arachnocampa flava, is known to possess true circadian regulation of bioluminescence: light:dark cycles entrain the rhythm of nocturnal glowing. Given the absence of natural light as a cue in caves, we addressed the question of whether cave populations of Arachnocampa tasmaniensis, a species known to inhabit caves as well as epigean environments, are rhythmic. We found that the major dark-zone cave populations of A. tasmaniensis maintain a high-amplitude 24-hour rhythm of bioluminescence, with the acrophase during external daylight hours. Populations of A. tasmaniensis in caves many kilometers apart show similar, but not exactly the same, timing of the acrophase. Systematic investigation of colonies in the dark zone of a single cave showed that some smaller colonies distant to the main ceiling colony, also in the dark zone, glow in antiphase. Periodic monitoring of a single colony over several years showed that the acrophase shifted from nocturnal to diurnal some time between October 2008 and January 2009. Prey availability was investigated as a possible zeitgeber. The acrophase of prey availability, as measured by light trapping, and the acrophase of bioluminescence do not precisely match, occurring 3 hours apart. Using in-cave artificial light exposure, we show that after LD cycles, cave larvae become entrained to bioluminesce during the foregoing photophase. In contrast, epigean larvae exposed to artificial LD cycles after a period of DD become entrained to bioluminesce during the foregoing scotophase. One explanation is that individuals within colonies in the dark zone synchronize their bioluminescence rhythms through detection and matching of each other ’s bioluminescence. 10acoupled oscillators10aepigean10aHypogean10amutual synchronization10atroglophile1 aMerritt, David, J.1 aClarke, Arthur, K.  uhttp://jbr.sagepub.com/content/26/1/3402164nas a2200133   4500008004100000245009200041210006900133300001200202490000700214520167200221100001901893700001901912856009901931       2008                        eng d00aCircadian regulation of bioluminescence in the prey-luring glowworm, Arachnocampa flava0 aCircadian regulation of bioluminescence in the preyluring glowwo  a319-3290 v233 aThe glowworms of New Zealand and Australia are bioluminescent fly larvae that generate light to attract prey into their webs. Some species inhabit the constant darkness of caves as well as the dim, natural photophase of rainforests. Given the diversity of light regimens experienced by glowworms in their natural environment, true circadian rhythmicity of light output could be present. Consequently the light emission characteristics of the Australian subtropical species Arachnocampa flava, both in their natural rainforest habitat and in artificial conditions in the laboratory, were established. Larvae were taken from rainforest and kept alive in individual containers. When placed in constant darkness (DD) in the laboratory they maintained free-running, cyclical light output for at least 28 days, indicating that light output is regulated by an endogenous rhythm. The characteristics of the light emission changed in DD: individuals showed an increase in the time spent glowing per day and a reduction in the maximum light output. Most individuals show a free-running period greater than 24 h. Manipulation of the photophase and exposure to skeleton photoperiods showed that light acts as both a masking and an entraining agent and suggests that the underlying circadian rhythm is sinusoidal in the absence of light-based masking. Manipulation of thermoperiod in DD showed that temperature cycles are an alternative entraining agent. Exposure to a period of daily feeding in DD failed to entrain the rhythm in the laboratory. The endogenous regulation of luminescence poses questions about periodicity and synchronization of bioluminescence in cave glowworms.1 aMerritt, David1 aAotani, Sakiko  uhttp://www.online-keys.net/sciaroidea/add01/Merrit_&_Aotani_2008_circadian_Bioluminescence.pdf