云南紫胶虫与粗纹举腹蚁之间的互利关系

为了明确云南紫胶虫Kerria yunnanensis和粗纹举腹蚁Crematogaster macaoensis之间的相互作用关系, 于2009年4月至2010年10月, 在云南省墨江县雅邑乡紫胶种植园, 结合野外调查和室内试验对比研究了粗纹举腹蚁取食人工食物、 云南紫胶虫排泄的蜜露和无食物的3种处理下粗纹举腹蚁个体体重和存活率的变化, 以及在粗纹举腹蚁垄断蜜露、 自然条件下和无蚂蚁照顾的3种处理下云南紫胶虫个体怀卵量、 虫体大小、 死亡率和生活史周期的变化。结果显示： 云南紫胶虫排泄的蜜露是一种高质量的食物资源, 能够稳定增加粗纹举腹蚁工蚁的体重百分比［人工食物（44.55%）>蜜露（25.81%）>无食物（-4.13%）］ （F_（2,54）=18.81; P＜0.01）, 并提高其存活率［人工食物（85.78%）>蜜露（82.48%）>无食物（78.74%）］ （F_（2,55）=7.31; P＜0.01）。粗纹举腹蚁取食蜜露的同时, 有利于增加单位面积上云南紫胶虫的雌虫数量［蚂蚁垄断蜜露（80.81%）>自然状态（75.55%）>无蚂蚁照顾（75.33%）］ （F_（2,143）=54.08; P＜0.01）, 提高云南紫胶虫的个体怀卵量［蚂蚁垄断蜜露（401.85粒）>自然状态（395.73粒）>无蚂蚁照顾（353.34粒）］ （F_（2,144）=4.82; P＜0.01）, 降低云南紫胶虫的死亡率［蚂蚁垄断蜜露（89.42%）<自然状态（89.78%）<无蚂蚁照顾（90.82%）］ （F_（2,146）=3.45; P＜0.05）; 云南紫胶虫虫体有变小的趋势［蚂蚁垄断蜜露（12.92 mm²）<自然状态（13.04 mm²）<无蚂蚁照顾（14.90 mm²）］ （F_（2,147）=10.88; P＜0.01）, 生活史周期变长［蚂蚁垄断蜜露（203.96 d）>无蚂蚁照顾（202.85 d）>自然状态（200.00 d）］ （F_（2,71）=19.77; P＜0.01）, 提示粗纹举腹蚁取食蜜露增加了云南紫胶虫的代谢压力。结果说明, 以蜜露为纽带的粗纹举腹蚁和云南紫胶虫之间的相互作用关系是兼性互利的。     

Life history,damage assessment and control of Trioza hopeae (Hemiptera: Psylloidea), a serious pest on Hopea odorata (Malvales: Dipterocarpaceae) in Vietnam

Young plants of the commercially important timber species Hopea odorata Roxb. are seriously damaged by the psyllid Trioza hopeae Burckhardt & Vu in nurseries in South Central and Southern Vietnam. Farmers routinely use Class 1 toxic insecticides to control the psyllids but these pose serious health risks in the urban environment. As a precursor to developing a pest management strategy, we studied the life cycle of T. hopeae and trialed several control measures. Trioza hopeae is polyvoltine with overlapping generations peaking in mid wet season. Females laid approximately 135 eggs; however, there was a natural attrition rate of about 80% in first‐instar nymphs due to the nymph's inability to find a suitable feeding site. Feeding nymphs induced pit galls on young H. odorata leaves and were present on all trees examined during the study. The pre‐adult life cycle lasted approximately 13 days and adult life span approximately seven days. Several toxic insecticides were found to be effective for controlling T. hopeae, but a novel non‐toxic alternative was equally as effective. We discuss these methods and potential biological control measures.     

Water balance in the Argentine ant (Linepithema humile) compared with five common native ant species from southern California

Abstract.  Little attention has been given to the effect of physiological limitations on the ability of introduced species to invade ecological communities. In the present study, the water balance of the invasive Argentine ant ( Linepithema humile ) is compared with five common ant species native to southern California. Total and critical water contents are measured, as well as rates of water loss and survival times. The results show that the body size of ant species has a strong effect on water balance, explaining between 99% of total and 90% of critical water content (i.e. the amount of water remaining when the ant becomes moribund). The measured survival times at 40 °C and approximately 0% relative humidity are shorter for L. humile than for the other five native ant species. The area-independent water-loss rate is higher for L. humile than for the other native ant species studied. This finding is corroborated by independent data using two different methods (i.e. gravimetric measurement and open-flow respirometry). Somewhat surprisingly, significant differences in the water-loss rates of different sizes of Solenopsis xyloni workers are found, even after adjusting for surface area. The area-independent water-loss rate is significantly lower for larger than for smaller workers. Consistent with circumstantial evidence from the field, the results suggest that the physiological constraints of invasive species, such as water-loss rates and critical water content, can limit their distribution and abundance not only at regional scales, but also at fine scales.     

Carbon and nitrogen contents of food bodies in three myrmecophytic species of <Emphasis Type="Italic">Macaranga</Emphasis>: implications for antiherbivore defense mechanisms

 In Macaranga myrmecophytes, differences in the production of the food bodies (FBs), on which symbiont ants feed, may relate to the intensity of antiherbivore defense by the ants. Interspecific comparisons among Macaranga species on such a mutualistic cost give important information on their strategies and evolution of antiherbivore defense. In this study, the carbon and nitrogen contents of FBs as well as the production rate of FBs were measured in three Macaranga species, M. winkleri, M. trachyphylla, and M. beccariana. There were significant differences in the production rates of FBs among species; the investment in FBs was greater in the Macaranga species in which ant defenses were more intensive. The carbon and nitrogen contents of FBs were significantly different among the three species, although they did not match the intensity of ant defense; the nitrogen content, especially, was greatest in the species of least intensive ant defense. It is suggested that Macaranga plants may have differentiated in the dependence on ant defense by controlling the total amount of nitrogen of FBs, not simply by nitrogen content. Received: January 19, 2001 / Accepted: December 23, 2001     

Not all ants are equal: obligate acacia ants provide different levels of protection against mega‐herbivores

In obligate ant–plant mutualisms, the asymmetric engagement of a single plant species with multiple ant species provides the opportunity for partners to vary in their behaviour. Variation in behaviour has implications for the interactions with third‐party species such as herbivores. This study assessed the effect of obligate ant‐mutualists (Crematogaster mimosae, Crematogaster nigriceps and Tetraponera penzigi) inhabiting the African ant‐acacia (Acacia drepanolobium) on three mega‐herbivore browsers: the Maasai giraffe (Giraffa camelopardalis tippelskirchi), the reticulated giraffe (Giraffa c. reticulata) and the black rhino (Diceros bicornis). Giraffes are abundant and wide‐ranging herbivores of the acacias, whereas black rhinos are localized and perennial herbivores of the acacias. Multiyear field studies comparing the ants’ aggressive behaviour and browsing by mega‐herbivores suggested differences between the tending abilities of the primary ant species inhabiting A. drepanolobium. Trees occupied by the aggressive ant species C. mimosae had significantly less browsing by giraffes and black rhino than trees occupied by other ant species. The results of this study provide evidence that ant‐mutualists on African acacias can serve as deterrents to mega‐herbivores and that different ant species vary in their tending abilities.     

Behavioural Interactions Between <Emphasis Type="Italic">Crematogaster brevispinosa rochai</Emphasis> Forel (Hymenoptera: Formicidae) and Two <Emphasis Type="Italic">Nasutitermes</Emphasis> Species (Isoptera: Termitidae)

In the savanna-like Brazilian biome caatinga, the arboreal and polydomous ant Crematogaster brevispinosa rochai can be found cohabiting with two closely related Nasutitermes species (N. corniger and N. ephratae). This ant occupies variably sized portions of the termite nests and maintains a physical separation with its hosts by plugging the cells of the boundary areas with fibrous material. Although all the analysed cohabiting C. b. rochai nests were queenless, they always contained brood, especially from male and female reproductive castes. Interaction experiments between workers of C. b. rochai and workers or soldiers of N. ephratae revealed a low level of aggressiveness between the two species that contrasts with the aggressiveness of both C. b. rochai and N. ephratae in encounters with other ant (Azteca cf. chartifex, Cephalotes pusillus) or termite (M. cf. indistinctus) species. The association could benefit both ants (additional nesting sites, brood rearing places) and termites (protection against predators, dead ants or ant refuses as source of nitrogen).     

Relationship between Plant Size and Ant Associates in Two Amazonian Ant‐Plants1

A survey of two Amazonian melastome ant‐plants, Maieta guianensis and Tococa bullifera, revealed a significant difference in plant size according to the species of ant inhabiting the plant. Plants with Crematogaster laevis, on average, were smaller than those with Pheidole minutula (in M. guianensis) and those with Azteca sp. (in T. bullifera). There is no evidence that these patterns were due either to the deterministic replacement of C. laevis by another ant species during host‐plant ontogeny or to a habitat effect on plant growth rates coupled with colony survival. More likely, the smaller size of C. laevis plants can be explained by its effects on host‐plant performance. Plants with C. laevis lost their associated ant colonies more frequently than plants with P. minutula and Azteca sp. Plants that lost their C. laevis either died, or more commonly, were severely defoliated. Defoliated plants, once sprouted, tended to become recolonized, but such recolonizations were not deterministic so as to favor one species over another. Plants with C. laevis showed similar, or only slightly greater, standing levels of herbivory than plants with P. minutula or Azteca sp. This suggests that when C. laevis is present, it confers some degree of protection to its hosts. It was found that early in colony development, queens of C. laevis moved off their host plants to build satellite nests in dead twigs on the ground, a behavior not seen in the other two species and one that possibly renders colonies more vulnerable to mortality from predation, flooding, or nest decay. Comparable 8¹⁵N values in C. laevis and P. minutula indicate that the two species are equally dependent on food supplied by the host plant.     

Isolation and characterization of microsatellite markers from the acacia-ant Crematogaster mimosae

We describe 10 microsatellite loci developed from Crematogaster mimosae, an ant species that nests mutualistically in Acacia drepanolobium trees in east Africa. Polymorphism ranged from 4 to 16 alleles per locus (mean = 7.3). Observed and expected heterozygosities ranged from 0.485 to 0.813 (mean 0.626), and from 0.502 to 0.894 (mean 0.674), respectively. These markers will foster studies of the population structure, colony structure, and reproductive strategies of these ants.     

Non-ant antiherbivore defenses before plant-ant colonization in Macaranga myrmecophytes

We examined changes in the intensity of non-ant defenses of three myrmecophytic Macaranga species before and after the initiation of symbiosis with ants in a Bornean dipterocarp forest. The intensities of non-ant defenses at different growth stages of each Macaranga species were estimated by measuring the survival rate of larvae of the common cutworm, Spodoptera litura, when the larvae were fed on fresh leaves from seedlings (saplings) at three growth stages of each Macaranga species. In all species, the intensity of the non-ant defenses when seedlings had not yet received symbiont foundress queens was significantly higher than that after ant defense was well established. These results support the hypothesis that myrmecophytic Macaranga may defend themselves sufficiently via non-ant defenses before beginning symbiosis with ants and that the intensity of non-ant defenses may decrease as the symbiont colony size increases. We suggest that, where the status of myrmecophytism changes as plant–ant colonies grow, the decrease in the intensity of non-ant defenses which we detected after the establishment of ant colonies might generate an optimal allocation of metabolic cost to ant and non-ant defenses under resource limitations. We also measured leaf toughness, which is considered to be one of the most important agents of non-ant defenses against herbivorous insects, at different plant stages to assess its contribution to the change in the intensity of non-ant defenses after ant colonization. However, we found no evidence that changes in leaf toughness have a significant effect on the change in balance of the two antiherbivory mechanisms. Received: February 2, 2001 / Accepted: August 21, 2001     

The Tropical Ant Mosaic in a Primary Bornean Rain Forest

In primary lowland rain forest in Brunei Darussalam, we studied arboreal ant communities to evaluate whether densities and spacing of spatially territorial taxa along 2.9 km of well-studied trails are consistent with existence of a continuous mosaic of dominant ants. A median intercolony distance of 24.5 m, about twice or less distances over which colonies of most included species regularly ranged, suggested a relatively continuous mosaic. Despite relying on nesting sites in preformed plant cavities, carpenter ants contributed > 70 percent of mapped colonies. Most belonged to the Camponotus ( Colobopsis ) cylindricus (COCY) complex, including SE Asia's 'exploding' ants. Their lack of aggression against certain Polyrhachis species was associated with interspecific territory sharing by members of the two groups, and with a dominance-discovery trade-off. Experimental approaches yielded evidence for two putative contributors to positive association. Larger-bodied Polyrhachis parasitize food-finding abilities of smaller, more populous Camponotus workers, and the two taxa cooperate in territorial defense. Highly territorial and predatory weaver ants ( Oecophylla smaragdina ) were an important component of the ant mosaic in primary forest, second only to codominant COCY and Polyrhachis taxa. Members of the genus Crematogaster were significantly associated with Oecophylla in baiting censuses and regularly monopolized near-nest baits to the exclusion of weaver ants. Litter ant abundances differed between territories of Oecophylla and less predatory COCY species, but direction of difference was inconsistent over time. The densely packed mosaic of spatially territorial, and differentially predatory, taxa in Bornean rain forest likely contributes to spatial variation in ant effects on plant and arthropod communities.