The ability of the amphipod Corophium volutator (Pallas) to follow chemical signals from con-specifics

The amphipod Corophium volutator (Pallas) is a tube-dwelling species that only occasionally leaves its burrow. Animals that do crawl on the sediment are mainly males, apparently in search of females. This study was designed to determine whether C. volutator males and females release chemical signals that attract con-specifics, and if so, whether these signals are gender specific. Laboratory experiments were conducted on the over-wintering generation during their reproductive season, using a Y-maze choice test apparatus. The results show that C. volutator females release chemical signals that attract males. In the field, the attractant may guide males in search of burrowed females. In addition, male odour tends to attract males, while females do not follow chemical signals from con-specifics. We thereby show on gender-specific chemical attraction of this species.     

Nutritional ecology of thalassinidean shrimps constructing burrows with debris chambers: The distribution and use of macronutrients and micronutrients

Four different approaches were combined to determine the nutritional relevance of debris chambers in the burrows of two thalassinidean shrimps: (1) the natural abundance of carbon and nitrogen stable isotopes in potential food sources, (2) their nutritional value based on the content and composition of essential nutrients, (3) a dual labelling experiment with shrimp in aquaria employing ¹⁵N- and ¹³C-labelled seagrass debris and (4) ration estimates using the acquisition rate of plant debris by the shrimps. The results of the four approaches confirmed the use of plant debris as a food source. Based on the natural abundance of stable isotopes, Corallianassa longiventris apparently relies on the chamber content and the burrow wall as sources of carbon and nitrogen, whereas Pestarella tyrrhena probably relies on ambient debris and on benthic foraminiferans and microphytobenthos in the surface sediment. Corallianassa longiventris obtains its essential nutrients predominantly from chamber debris and to a lesser extent from its burrow wall, P. tyrrhena from chamber debris, the burrow wall and the surface sediment. Among the essential nutrients, those amino acids commonly deficient to deposit feeders were particularly enriched in the burrow environments of the two shrimps. Highly unsaturated fatty acids (HUFAs) were lacking in all of C. longiventris potential food sources; this species may either be able to synthesize them de novo from linolic acid or may use another unknown source. For P. tyrrhena, surface sediment and chamber debris represent potential HUFA sources. The most probable thiamine and β-carotene supplier for C. longiventris is the chamber debris, for P. tyrrhena again the surface sediment. In both species, the rate of debris introduction into the burrow is sufficient to meet the nutritional demand.     

Does the presence of the SW Atlantic burrowing crab Chasmagnathus granulatus Dana affect predator–prey interactions between shorebirds and polychaetes?

The burrowing crab Chasmagnathus granulatus is an important bioturbator that generates dense burrow assemblages (crab beds) characteristic of intertidal habitats of SW Atlantic estuaries. Crab bioturbation affects the topography and hydrodynamics of the sediment, increasing sediment water and organic matter content, decreasing sediment hardness and changing the grain size frequency distribution. In this study, we found that burrowing crabs can decrease the impact of predation by shorebirds on polychaetes. The polychaete Laeonereis acuta Treadwell has U-shaped burrows outside crab beds, which are associated with surface deposit-feeding while their burrows are mainly I-shaped inside which is associated with subsurface deposit feeding behavior. This pattern is likely the result of larger vertical sediment mixing inside crab beds due to crab burrowing. As a result of their feeding strategy, polychaetes appear on the surface more often outside crab beds, which increases their availability for shorebirds. In addition, shorebird species differentially use crab beds. The White-rumped Sandpiper, Calidris fuscicollis Vieillot, preferentially forage outside crab beds, meanwhile the Two-banded Plover Charadrius falklandicus Latham forage more frequently inside crab beds. However, experiments excluding shorebirds inside and outside crab beds showed negative effects of shorebirds only outside crab beds. Thus, our results show that the SW Atlantic burrowing crab C. granulatus affects the strength of the predator–prey interaction between shorebirds and polychaetes.     

A biological assessment of Glypta variegata (Hymenoptera: Ichneumonidae) as a parasitoid of Choristoneura rosaceana (Lepidoptera: Tortricidae)

In laboratory trials, Glypta variegata, a common endoparasitoid of leafrollers in North America, successfully parasitized first through third instar Choristoneura rosaceana and first to fourth instar Pandemis limitata. Significantly more second instar C. rosaceana were parasitized when temperatures fluctuated between 30.3 and 12.0°C (16 L:8 D) than when temperatures fluctuated between 17.5 and 4.0°C (12 L:12 D), similar to fall conditions in southern British Columbia, Canada. Under the warmer simulated summer conditions, an average female wasp began to parasitize C. rosaceana 8 days post-emergence (range: 4-16 days), lived 31 days (range: 24-37 days) and successfully parasitized 28 larvae (range: 1-89). When parasitized, C. rosaceana larvae consumed less food in their last two instars than did unparasitized female larvae.     

Effects of quantitative and qualitative variation in phenolic compounds on feeding in three species of marine invertebrate herbivores

The deterrent effects of brown algal phenolic compounds and the terrestrial polyphenolic tannic acid on feeding by three species of invertebrate herbivores from central California, including the gastropods Tegula funebralis (Adams) and Tegula brunnea (Phillipi) and the echinoid Strongylocentrotus purpuratus (Stimpson) were examined. Algal phenolics used were the monomeric phenolic phloroglucinol and polyphloroglucinols from Fucus vesiculosus (Linnaeus), Halidrys siliquosa (Linnaeus) Lyngbye and Eisenia arborea Areschoug. All of the polyphenolics deterred feeding by all three herbivores at concentrations of 5 mg · ml⁻¹ in agar disks. Concentrations of 2 mg · ml⁻¹ also generally deterred feeding by the gastropods (these levels were not tested against S. purpuratus). Relative amounts of deterrence by different compounds were similar, especially for the gastropods. Phloroglucinol deterred feeding by the echinoids, but not by T. funebralis. Responses of the echinoids were otherwise similar to the gastropods, but more variable. I also demonstrated deterrence of S. purpuratus by tannic acid using the “tanned” kelp technique of Steinberg (1985). Reactivity of the different phenolic compounds in the Folin-Denis procedure, a common colorimetric assay used to estimate levels of phenolics in plant tissue, was similar. This suggests that measuring phenolic levels in brown algae by this technique will not be greatly confounded by the occurrence of different kinds of phenolic molecules in different brown algae. This result, in combination with the similarity of the deterrent effects of the compounds used in this study, increases the validity of previous studies in the northeastern Pacific Ocean which correlate algal phenolic levels and diets or feeding preferences of invertebrate herbivores. For plants and herbivores in this region, this assay is a reasonable measure of a biologically meaningful phenomenon — levels of phenolic deterrents in the algae.     

Post-bloom feeding of Calanus finmarchicus copepodites: Selection for autotrophic versus heterotrophic prey

Feeding and faecal pellet production of late copepodite stages of Calanus finmarchicus were measured in mixtures of cultured autotrophic and heterotrophic food, as well as in a natural post-bloom plankton assemblage, in order to evaluate food selection and its potential effect on sedimentation of organic matter. Calanus finmarchicus consistently selected for diatoms, both in mixtures with the heterotrophic dinoflagellate Oxyrrhis marina, and in natural seston containing dinoflagellates, ciliates and flagellates. Similarly, the filtration, ingestion and faecal pellet production rates were significantly higher feeding on diatoms than when feeding on other food species. Calanus finmarchicus selection appeared relatively inflexible, so that changes in seston composition induced large changes in diet quantity and composition. Our results support the traditional view of C. finmarchicus as a major grazer of diatoms, and suggest potentially high post-bloom faecal pellet production rates.     

The feeding behaviour of a deep-sea holothurian, Stichopus tremulus (Gunnerus) based on in situ observations and experiments using a Remotely Operated Vehicle

Using a Remotely Operated Vehicle (ROV) to deploy an in situ cage experiment incorporating fluorescent Luminophore particle tracers, the gut throughput time of the deposit feeding holothurian, Stichopus tremulus (Gunnerus) was determined as 23.73 h (S.D.±2.3). For a range of individuals examined at different depths (350-500 m) and locations, throughput times varied between 19 and 26 h irrespective of animal size or gut tract length. In situ video observations of feeding behaviour showed that this species uses fine oral papillae in a ‘sweeping’ motion to target particles on the seafloor. Following detection of a food source fine-branched digitate tentacles collect a large range of sediment fragments from the seabed. The main types of particles ingested include silica fragments (<20 >500 μm), pelagic foraminifera, benthic foraminifera, fine phytodetrital remains and occasional larger rock fragments (∼1 cm). Ingested sediment consisted mainly of very fine silica fragments (∼50 μm) accounting for over 50% of the total gut contents. Frame-by-frame video analysis revealed that the particle handling time (i.e. the time taken for a tentacle insertion and the subsequent collection of food) was found to be ∼54 s. Only 10 of the 20 feeding tentacles were simultaneously employed during feeding. Use of tentacles appeared to be in sequence, alternating between the reserve and active tentacles. Estimating the rate of movement over the seabed and the total effective capture area of each tentacle, the impact of this animal on the turnover and quality of surface sediment at this deepwater site is potentially substantial. The in situ experiments provided a significant improvement over previous methods used to investigate deep-sea deposit feeders and represent a useful concept for further in situ deep-sea research using an industrial ROV.     

Lugworm exclusion experiment: Responses by deposit feeding worms to biogenic habitat transformations

On six 400 m² plots over 3 years, we excluded the sessile subduction and conveyer-belt feeding polychaete Arenicola marina which generates a pit-and-mound topography at the sediment surface from intertidal sands near the island of Sylt, Germany. This experiment was used to test whether other abundant deposit feeding polychaetes (the discretely motile and surface feeding ragworm Nereis diversicolor and the subsurface-feeding, motile orbiniid polychaete Scoloplos cf. armiger) benefit from competitive release. Ragworms took advantage from the absence of lugworms. Presumably they responded to a more stable and nutritious surface layer at lugworm exclusion plots (relief from inhibitive bioturbation). Contrary to this, S. cf. armiger was negatively affected by the exclusion of A. marina. It may have suffered from higher sulfide concentrations in the less irrigated and less permeable sediment where lugworms were absent. For adult worms of both species these results were consistent in 2 out of 3 years examined. Recruitment by N. diversicolor was highly variable between years and occurred either irrespective of experimental treatments or the response was inconsistent. Juveniles of S. cf. armiger benefited from the presence of A. marina and aggregated near lugworm tail shafts where inflow of oxygen rich water was high and sulfide concentrations were low. Biogenic habitat mediated effects of lugworms on both deposit feeders were in the same order of magnitude as abundance variation in space and time. Thus, A. marina was one of the key factors structuring the deposit feeding community. It is suggested that arenicolids modify the composition of the associated polychaete assemblage primarily through habitat transformation.     

Morphology and germination characteristics of the cysts of Chattonella ovata (Raphidophyceae), a novel red tide flagellate in the Seto Inland Sea, Japan

To elucidate the mechanism of bloom outbreaks of Chattonella ovata (Raphidophyceae), we investigated the cysts of C. ovata and succeeded in finding them from the bottom sediments of Hiroshima Bay. The morphology of the cysts was mostly hemispherical in shape, with a diameter of ca. 30 μm and height of ca. 20 μm. The cysts were usually adhering to solid materials, such as diatom frustules, yellow-greenish in color and had several dark brown grains. The cyst wall was smooth and had no ornamentation. Because the morphological characteristic of the cysts was in general agreement with those of Chattonella antiqua and Chattonella marina, it was difficult to differentiate the cysts of these three species. Germination of the cysts of C. ovata was observed at temperatures from 17.5 to 30 °C, but not at 15 °C or below. The number of the germinated cysts increased with increasing temperature and the optimum temperature for germination was 30 °C. Although cysts of C. antiqua and C. marina germinated at temperatures from 15 to 30 °C, optimum temperature of germination was 22.5 °C. The lower limit and optimum temperatures for germination of C. ovata cysts was higher than for C. antiqua and C. marina. The role of cysts in the population dynamics of C. ovata is discussed.     

Biology and prey range of Cryptognatha nodiceps (Coleoptera: Coccinellidae), a potential biological control agent for the coconut scale, Aspidiotus destructor (Hemiptera: Diaspididae)

Cryptognatha nodiceps Marshall is an important natural enemy used in biological control programmes against Aspidiotus destructor (Signoret), an introduced pest of coconut in many countries. In order to increase our understanding of C. nodiceps, the present study to quantify aspects of the developmental, reproductive and feeding biology under constant environmental conditions (26±2°C, 55-65% RH) was carried out. In addition, methods for culturing the scale and the beetle were developed. The average duration of development was 19.2±0.1 days for males and 19.6±0.2 days for females. Female longevity and lifetime fecundity was 35.6±5.1 days and 141.0±35.6 eggs, respectively. Life table statistics were as follows: reproductive rate, 9.99, intrinsic rate of increase, 0.09, finite rate of increase, 1.1, doubling time, 7.8 days and generation time, 41.1 days. Studies on feeding biology showed that C. nodiceps was oligophagous. The coccinellid fed and reproduced on prey species in two families, Diaspididae and Coccidae. Adults also fed on the coconut whitefly Aleurodicus cocois (Curtis) (Aleyrodidae) but no reproduction occurred on this prey. Aphididae, Psyllidae and Pseudococcidae were not fed upon.     

Production d'NH4 par la crevette Crangon crangon L. dans deux écosystémes côtiers. approche expérimentale et étude de l'influence du sédiment sur le taux d'excrétion

Estimation of the ammonia production of the shrimp C. crangon in two littoral ecosystems (oligotrophic sand and eutrophic mud) was determined in winter and summer conditions from laboratory observations in experimental microcosms. The ammonia excretion rate of C. crangon was not influenced by either the sediment type or the ammonia concentration of the overlying water; on the other hand, the mean excretion rate and the response to initial handling stress increased markedly as shrimp were deprived of soft substratum.

The daily ammonia production of C. crangon was 16 μmol NH₃ · g ⁻¹ wet wt · day ⁻¹ in winter and 40 μmol in summer. A gross production of 12 μmol NH₃ · m⁻² · day ⁻¹ and 300–700 μmol μ m⁻² · day⁻¹, respectively, could be expected in the two ecosystems studied. This would account for 5% (winter) and 2–4% (summer) of the total NH⁺₄ flux at the sediment-water interface. The contribution of the excretion of all macrofauna to the NH⁺₄ flux from the sediment is discussed.     

西藏马鹿与同域野生有蹄类、家畜草青期食性比较

西藏马鹿为我国特有种,曾一度被认定为野外灭绝。在其生境中有多种食性相近的野生有蹄类及家畜同域分布,探究青藏高原特殊环境下西藏马鹿与这些有蹄类的食物资源种间竞争与共存关系十分必要。2013年和2014年8—9月,采用粪便显微分析法确定了桑日县西藏马鹿自然保护区西藏马鹿、白唇鹿、藏原羚、牦牛、山羊草青期食物组成,并比较分析了西藏马鹿与同域野生有蹄类、家畜之间的食物重叠和分化状况。结果表明: 西藏马鹿与其他有蹄类具有相似的可食植物种类组成,但所占食谱比例不同。西藏马鹿主要可食植物多为其他有蹄类次要可食植物,其中弱小火绒草为西藏马鹿(在动物食谱中的百分比为11.2%)与牦牛(10.2%)共同的主要食物,西藏柳为西藏马鹿(9.6%)和白唇鹿(11.4%)共同的主要食物。从科级水平来看,豆科植物为西藏马鹿(21.4%)与藏原羚(42.5%)的共同主要可食植物,莎草科植物为白唇鹿(49.2%)、牦牛(33.4%)、山羊(50.3%)的共同主要可食植物。菊科植物作为西藏马鹿(29.6%)的主要可食植物,也是白唇鹿(7.6%)、藏原羚(11.6%)、牦牛(17.3%)和山羊(14.1%)的次要可食植物。禾本科植物作为西藏马鹿(7.1%)次要可食植物,较其他4种有蹄类(白唇鹿13.6%、藏原羚12.3%、牦牛11.5%、山羊16.0%)所占比例低。西藏马鹿与其他有蹄类食物重叠度均高于0.5,与牦牛的重叠度最高(0.65)。西藏马鹿食物多样性指数(1.32)、均匀度指数(0.37)和生态位宽度指数(15.79)均较高。与2007—2008年相比,西藏马鹿食物组成变化较大,豆科植物比例增大,莎草科植物比例降低,食物质量总体有所提高。西藏马鹿与家畜之间存在较高的食物资源竞争,这将进一步影响西藏马鹿的分布范围和生存空间。     

Critical thermal maximum and body water loss in first instar larvae of three Cetoniidae species (Coleoptera)

Critical thermal maximum (CT_max) and body water losses were measured in first instar larvae of Gnorimus nobilis, Osmoderma eremita (Trichiinae) and Cetonischema aeruginosa (Cetoniinae) when air temperature was increased gradually (0.5 °C/min) from 20 °C to the critical thermal maximum (CT_max), in dry air (near 0% R.H.).

The CT_max was significantly lower in O. eremita (45.6±0.7 °C) than in G. nobilis (48.5±0.6) and C. aeruginosa (51.4±0.9 °C).

An increase of 10 °C (30–40 °C) induced a 2-fold increase of the water loss in C. aeruginosa and O. eremita (Q₁₀=2.10±0.12 and 2.13±0.20, respectively). In the range from 40 to 45 °C to CT_max a strong increase of the water loss was observed in O. eremita and C. aeruginosa, respectively. Body water losses were significantly lower in C. aeruginosa than in O. eremita and G. nobilis over the range 20 °C—CT_max; no significant difference occurred between G. nobilis and O. eremita.     

Feeding ecology of the earliest vertebrates

Based on protochordates and extant fish, the earliest Palaeozoic vertebrates were microphagous suspension-feeding animals that pumped food-carrying water very slowly and thus required highly concentrated suspensions. Such conditions exist in benthic (not open water) aquatic environments. Feeding modes which on the basis of extant fish are closely related to benthic microphagous suspension feeding include deposit feeding, epilithic algal scraping, and macrophagous suspension feeding; early jawless vertebrates are predicted to have included all these feeding types. The gnathostome condition is predicted to have followed an initial switch from feeding on suspensions to taking tiny individual food particles (microphagous suspension-feeding → microphagous particulate-feeding → macrophagous particulate-feeding).     

超声波对铜绿微囊藻与蛋白核小球藻生理特征及竞争生长的影响

铜绿微囊藻是常见的水华蓝藻,常常在湖泊中与蛋白核小球藻共存或竞争生长。超声波可用于藻华即时治理,能够降低藻类生理活性,影响藻类生长,还可能改变藻类种间竞争关系。为了探究超声胁迫(35 kHz,0.035 W·cm^-3)对铜绿微囊藻与蛋白核小球藻的生理特征及种间竞争的影响,本研究设置纯藻组和1:1混合组(细胞浓度比)进行试验。结果表明: 铜绿微囊藻对超声胁迫更加敏感。超声处理600 s后,铜绿微囊藻的光合活性(F_v/F_m)和酯酶活性存在显著变化,纯藻组和混合组的F_v/F_m分别降低了51.8%和64.7%。而各组中蛋白核小球藻的光合活性变化较小。同时,铜绿微囊藻释放的荧光溶解性有机物(类色氨酸、类酪氨酸、类富里酸物质)含量多于蛋白核小球藻。两种藻的细胞浓度对超声波的响应也不同,蛋白核小球藻变化较小,而铜绿微囊藻的细胞浓度出现不同程度的下降。尤其是600 s超声处理大幅降低了混合组中铜绿微囊藻的细胞浓度(-42.6%),在超声胁迫解除后的8 d内蛋白核小球藻占优势,种间关系由铜绿微囊藻单边抑制蛋白核小球藻转变为两者互相抑制。在超声处理后,铜绿微囊藻的活性能够逐渐恢复,为了提高控藻效果的持久性,建议在一周后再次进行超声处理。     

啃食性端足类强壮藻钩虾对筼筜湖三种大型海藻的摄食选择性

为了评估啃食性端足类强壮藻钩虾Ampithoe valida对筼筜湖大型海藻群落的影响,作者在实验室内开展了强壮藻钩虾对筼筜湖三种大型海藻(绿藻石莼Ulva lactuca和根枝藻Rhizoclonium sp.、红藻细基江蓠繁枝变种Gracilaria tenuistipitata var. liui)的摄食实验,并分析了大型海藻的营养价值是否对强壮藻钩虾的摄食选择产生影响。结果显示,在无选择性摄食实验中,强壮藻钩虾的摄食率与海藻的干湿比和鲜藻总有机碳含量有着明显的负相关关系,这表明强壮藻钩虾有明显的补偿摄食行为,能通过增加低营养价值藻类的摄食量来满足自身代谢的需求。强壮藻钩虾对绿藻石莼和根枝藻有明显的摄食偏好,对它们的摄食率分别占总摄食率的40.6%和57.1%,而红藻细基江蓠繁枝变种则属于偶然性摄食的种类,海藻的营养价值并没有对强壮藻钩虾的摄食选择产生影响。不过,强壮藻钩虾对绿藻的摄食偏好并没有在筼筜湖形成一个以红藻占主导的大型海藻群落,这可能是由于筼筜湖超富营养化的水体使得来自强壮藻钩虾的下行控制已经无法抑制来自超富营养化的水体通过上行控制对绿藻生长的促进作用。     

虾池拟柱胞藻爆发的生态因子调查

2002～2003年,在广东珠三角地区凡纳滨对虾(Litopenaeus vannamei)低盐度养殖虾池水体生态的调查过程中发现部分虾池爆发拟柱胞藻(Cylindrospermopsis raciborskii).在调查的低盐度虾池中,共统计20个拟柱胞藻爆发的虾池,其种群密度平均高达7.74×10⁷ filaments·L^-1,平均优势度达47.0%.虾池水体平均水温为30.3℃,pH为8.9,盐度1.4,透明度19cm,化学耗氧量为24.3mg·L^-1.拟柱胞藻爆发的虾池水体环境表现为高水温、高pH、高有机质、低盐度且水体不断被搅动;通常爆发在对虾养殖的中后期富营养化水体.调查发现大量的拟柱胞藻对虾池其它藻类和微生物菌群表现一定的抑制作用,蓝纤维藻和小环藻等少数藻种可与拟柱胞藻形成共优势种.拟柱胞藻为广东珠三角凡纳滨对虾低盐度虾池重要优势藻种,且以螺旋型为主.     

Influence of oxygen on ethanol and xylitol production by xylose fermenting yeasts

The behaviour of Pichia stipitis, Pachysolen tannophilus, Candida shehatae and Candida parapsilosis was investigated to select the most suitable yeast to convert xylose either to ethanol or to xylitol, with little or no formation of by-products. The aeration rate was used as a variable parameter. P. stipitis and C. parapsilosis were the most effective producers or ethanol and xylitol, respectively, both reaching productivities at very low levels of oxygenation. With P. stipitis, better ethanol productivity was attained under microaerobic conditions (K_La = 4·8 h⁻¹) while with C. parapsilosis high yields and rates of xylitol production were detected at K_La values of about 16·3 h⁻¹. P. tannophilus and C. shehatae showed lower performances under all conditions used while changes in oxygenation modified the ratio of ethanol to xylitol produced by these yeasts, suggesting that they are more dependent on the oxygen power input than P. stipitis and C. parapsilosis. The influence of oxygen transfer rates on ethanol and xylitol formation with the best producers is discussed.     

Thermoregulatory use of heat increment of feeding in the tawny owl (Strix aluco)

The heat increment of feeding (HIF) was investigated in the tawny owl (Strix aluco) in central Norway (63°N, 10°E), close to the northern limit of its distribution. HIF was measured as the increase in heat production (measured as oxygen consumption) after force-feeding the owls with laboratory mice at thermoneutral conditions (20 °C) and during cold-exposure (5 °C and −5 °C). The basal metabolic rate of the owls (mean mass 419 g) was 4.39 kJ h⁻¹ and the lower critical temperature was approximately 16 °C. During cold conditions, HIF substituted for thermogenesis, and at an ambient temperature of −5 °C the substitution was complete. Calculations indicate that the substitution by HIF may save the owls as much as 60% of their daily thermoregulatory costs. This corresponds to about 10% of their total daily energy budget.     

春季东海中华哲水蚤对有害藻华物种的选择性摄食

2005年4月27日—6月5日在东海有害藻华高发区的6个典型站位采样,分析了浮游植物的群落结构,并采用现场实验研究了中华哲水蚤(Calanus sinicus)的选择性摄食.结果表明,中华哲水蚤对浮游植物的选择性摄食具有食物密度依赖性.低浮游植物细胞丰度下中华哲水蚤具有明显的选择性摄食行为,高浮游植物细胞丰度下中华哲水蚤摄食选择性由偏好转变为排斥,浮游植物细胞丰度329 cells·ml^-1是中华哲水蚤由偏好趋于排斥摄食的阈值.中华哲水蚤的选择性摄食还与食物组成有关,对于食物中的微型浮游动物,中华哲水蚤无选择性或排斥摄食.有害藻华发生区中华哲水蚤对具齿原甲藻(Prorocentrum dentatum)的偏好摄食以及对米氏凯伦藻(Karenia mikimotoi)的排斥摄食,促使藻华的物种演替最终向米氏凯伦藻水华方向发展.