Substrate moisture,particle size and temperature preferences of trap‐building larvae of sympatric antlions and wormlions from the rainforest of Borneo

1. Larvae of antlions (Neuroptera: Myrmeleontidae) and wormlions (Diptera: Vermileonidae) display a convergently evolved sit‐and‐wait hunting strategy of building pitfall traps in sandy areas. This study investigated a sympatric population of antlions and wormlions in the lowland rainforest of Borneo for substrate moisture, particle size and temperature preferences. It was hypothesised that these animals would show different preferences regarding these microhabitat traits. 2. The results showed that antlions had a higher aversion to moisture compared with wormlions, but that wormlions had a higher preference for small‐particle sand. Furthermore, thermal preferences in antlions and wormlions were significantly different, with antlions choosing higher temperatures. 3. The detected differences between antlions and wormlions might contribute to their niche partitioning in the mixed Bornean population and thus facilitate coexistence of these animals. It is possible that the hotter and dryer microhabitat edges are preferred by antlions.     

Detection of ALMB-toxin in the Larval Body of Myrmeleon bore by Anti-N-terminus Peptide Antibodies

Antibodies were raised against a synthetic antigen carrying the N-terminus peptide of ALMB-toxin, which had been isolated from the antlion, Myrmeleon bore, that exhibited high specificity to the toxin. Analyses with the antibodies showed the toxin to be present mainly at the larval stage and localized in a region from the thorax to abdomen of the larval body.     

中国蚁蛉属一新纪录种(脉翅目,蚁蛉科)

记述蚁蛉科Myrmeleontidae蚁蛉属Myrmeleon中国1新纪录种,狭翅蚁蛉Myrmeleon trivialis Gerstaecker,1885;提出藏蚁蛉Myrmeleon zanganus Yang,1987为狭翅蚁蛉Myrmeleonon trivialis Gerstaecker,1885的新异名.研究标本保存在中国农业大学昆虫标本馆、匈牙利绍莫吉州博物馆和德国格赖夫斯瓦尔德大学动物博物馆.     

锈翅蚁蛉(脉翅目:蚁蛉科)的发育生物学研究

锈翅蚁蛉为全变态类昆虫,在贵州省一年发生1代,11月下旬开始越冬,各龄幼虫均可越冬,次年3月苏醒.在室内饲养条件下,卵期13 d±0.56 d,幼虫期63.58 d±1.81d,蛹期26.35 d±1.14 d,成虫期20 d± 1.06 d.结合野外调查和室内饲养,详细描述了锈翅蚁蛉各虫态的形态特征,幼虫的筑穴、捕食、蜕皮、化蛹、羽化以及成虫的捕食、交配等行为习性.     

Pit-Building Decisions of Larval Ant Lions: Effects of Larval Age, Temperature, Food, and Population Source

Foraging decisions are an integral component of growth and maintenance and may reflect both environmental and genetic effects. We used a common garden experiment to evaluate the effects of food, temperature, and population source on pit-building decisions of the larval ant lion Myrmeleon immaculatus. In a laboratory common garden experiment, first-instar larvae from two southern (Georgia, South Carolina) and two northern (Connecticut, Rhode Island) populations were reared for 14 months in incubators under high- and low-food and high- and low-temperature regimes. For all populations, there was no effect of larval age on pit-building behavior. All larvae built and maintained pits more frequently at high temperatures than at low temperatures, and larvae in the low-food treatments built and maintained pits more frequently than larvae in the high-food treatments. Larvae from the southern populations built and maintained pits more frequently than larvae from northern populations. These results suggest that regional differences in foraging behavior may contribute to latitudinal gradients in life history strategies seen in this insect.     

穴蚁蛉幼虫期的食物量对各虫态历期的影响研究

穴蚁蛉在自然条件下１年发生１代,本实验证明,不同的饲食频率可影响幼虫的发育历期,在每天饲给１头米蛾成虫的情况下,１年可发生３代。１个世代可以在全历期都处于长日照和没有低温的条件下完成,其发育可以不需要光周期变化诱发,１５日饲食１次的穴蚁蛉,３龄 虫     

Low Density of Ant Lion Larva (Myrmeleon crudelis) in Ant‐Acacia Clearings: High Predation Risk or Inadequate Substrate?1

We experimentally determined whether the low density of antlion larvae found in ant‐acacia clearings is due to high levels of ant predation or an inadequate substrate for pit‐trap construction. Pit establishment was more affected by soil improvement than by the exclusion of ants, suggesting that soil condition is the main factor that affect antlions’density. The low density of this ant‐predator in ant‐acacia clearings may be considered as an indirect advantage of the ant's pruning behavior.     

穴蚁蛉的自然种群动态

本文主要报道了穴蚁蛉 Myrmeleon(Morter) sagax(Walker)幼虫的野外自然种群数量动态。穴蚁蛉 1年发生 1代 ,在自然界其幼虫 3～ 5月份数量平稳略有下降 ,5、6月间数量迅速下降 ,6月初数量最少 ;7～ 9月份数量迅速上升 ,而后下降 ;新一代穴蚁蛉幼虫 (蚁狮 )在 6月份出现。其种群 ,秋季以 1龄幼虫数量为多 ,冬季主要以 2龄幼虫为主越冬 ,春季以 3龄蚁狮占优势。春季野外采集来的蚁狮 ,在每日光照 14小时、每周两饲 (每次饲 1头米蛾 Corcyra cephalonica成虫 )的条件下饲养 ,结果发现 ,采集回时处于 3龄期的蚁狮比自然界大约提前 1个月结茧化蛹和羽化 ;而采集回时处于 2龄期的蚁狮则和自然界中的情况基本一致。     

Bergmann's rule in larval ant lions: testing the starvation resistance hypothesis

Abstract.  1. Body size of the ant lion Myrmeleon immaculatus follows Bergmann's rule – an increase in body size towards higher latitudes. The hypothesis that ant lion body size is larger in the north as an adaptation for starvation resistance was tested.
2. In a laboratory experiment testing starvation resistance, survivorship curves differed among 10 ant lion populations for both a starved and a fed treatment.
3. The average number of months survived by each population was correlated positively with latitude for both treatments. Across both treatments and all populations, large individuals survived longer than small individuals; however individuals from high latitudes had higher survivorship, even after factoring out variation due to initial body size.
4. These results suggest that starvation resistance may be an adaptation for coping with reduced prey availability in high latitudes. Starvation resistance may contribute to latitudinal gradients in body size of ant lions and other ectotherms.     

Pit relocation by antlion larvae: A simple model and laboratory test

Summary We generated a computer model to analyse the effects of shadow competition for sit-and-wait predators, particularly antlion larvae. The model used a simple foraging assessment rule to determine the quality of an antlion's location, and antlions relocated randomly in their habitat when a location proved to be of low quality. Shadow competition, or competition for food caused when one sit-and-wait predator intercepts moving prey before a second sit-and-wait predator is encountered, was incorporated into the model by restricting antlions to a bounded arena, and having prey for the antlions enter from the arena periphery. Antlions responded to shadow competition by relocating their pits to peripheral areas of their habitat. This peripheral accumulation of pits was most pronounced when antlion densities were high, and when prey availabilities were intermediate. An experimental test with the antlionMyrmeleon immaculatus supported the importance of shadow competition as a cause of observed pit distributions. Only the treatment which incorporated shadowing had pit distributions near the periphery, while the pit distributions in the control treatments did not differ from randomly generated distributions. We conclude that shadowing can influence sit-and-wait predator distributions when the prey distributions and movement patterns generate the conditions necessary for shadowing. But when prey availability is unpredictable, making assessment of patches difficult, or when prey do not originate in the periphery of the habitat, other factors, such as temperature or moisture, could be more important.