Carbon isotope signatures reveal that diet is related to the relative sizes of the gills and palps in bivalves

In marine bivalves, the relative sizes of the gills and palps appear to be a useful functional trait that reflect feeding mode, i.e. suspension feeders have relatively larger gills than palps for pumping, whereas deposit feeders have relatively larger palps than gills for sorting. Also, within a species, the relative sizes of the gills and palps are related to changes in local food conditions. However, there is still no firm evidence showing that differences in the relative gill and palp sizes between species are related to diet selection. Based on the knowledge that carbon and nitrogen isotope signatures of an animals tissues reflect past diet, we compared the relative gill and palp sizes of bivalves from Roebuck Bay, northwestern Australia with their carbon and nitrogen isotope signatures. The carbon isotope signatures distinguished clear differences in diet between bivalves along a gradient from suspension to deposit feeding, and strikingly this pattern was closely followed by the relative sizes of the gills and palps of the bivalves. This study confirms that relative gill and palp sizes in bivalves are a functional trait that can be used to compare resource use between species. Furthermore, these data may suggest that morphospace occupation, as determined by relative gill and palp sizes of bivalves, could reflect a gradient of resource use between species.     

The articulation of cricket palps: morphology and movement patterns in behaviour

ABSTRACT. The morphology of the palp joints in Gryllus bimaculatus DeGeer is described in the context of their use in various behavioural situations. Two patterns of movements are distinguished: the goal-directed movement of each individual palp, as seen during grooming and food intake actions, and the rhythmic probing movement of the two maxillary palps together during exploratory behaviour and walking. Their details were studied by single frame analysis of video and cine records. The functional characteristics of the maxillary palps with regard to the dimensions of space within which they move in these patterns ('operational space') and the potential sensory stimuli they receive ('reception space') are compared with those of the antennae and discussed from the viewpoint of division of labour.     

星豹蛛求偶和交配行为

以星豹蛛(Pardosa astrigera)为研究对象,在室内对其求偶和交配行为进行了描述。雄蛛"俯卧撑"式动作(push-up)在求偶中具重要作用。交配初期,两侧触肢交替插入;随交配进行,单侧触肢连续插入3~5次后才换另一侧触肢插入,触肢每插入一次,基血囊膨大多次。完整交配一次雄蛛触肢器平均插入次数为29·625。交配前求偶时间、交配持续时间和有效交配时间分别平均为6min、32min25s和11min11s。星豹蛛雄蛛可进行多次交配,而雌蛛一般为单次交配。雌蛛交配状态(是否已经交配)影响其同类相食行为,已交配雌蛛对雄蛛同类相食率显著高于未交配雌蛛对雄蛛同类相食率。     

Copulation in the lycosid spider Schizocosa saltatrix (Hentz): An analysis of palpal insertion patterns

Copulation in this wolf spider species was characterized by a pattern which involved successive isertions of one palp before a shift was made to the opposite palp. The observed pattern is probably characteristic for the genus. The duration of mating and number of insertions were relatively great in comparison with other lycosids. In all cases, insertion duration was positively linearly correlated with the numerical sequence of insertion. Fatigue was hypothesized to be the underlying factor which produced the incremental change in insertion duration. Partial or complete independence of the control mechanism of each palp was suggested by the differences in certain aspects of insertion between the right and left palps in some of the males.     

Multimodal chemosensory integration through the maxillary palp in Drosophila

Drosophila melanogaster has an olfactory organ called the maxillary palp. It is smaller and numerically simpler than the antenna, and its specific role in behavior has long been unclear. Because of its proximity to the mouthparts, I explored the possibility of a role in taste behavior. Maxillary palp was tuned to mediate odor-induced taste enhancement: a sucrose solution was more appealing when simultaneously presented with the odorant 4-methylphenol. The same result was observed with other odors that stimulate other types of olfactory receptor neuron in the maxillary palp. When an antennal olfactory receptor was genetically introduced in the maxillary palp, the fly interpreted a new odor as a sweet-enhancing smell. These results all point to taste enhancement as a function of the maxillary palp. It also opens the door for studying integration of multiple senses in a model organism.     

Morphology of anterior regeneration in two spionid polychaete species: implications for feeding efficiency

Abstract. In marine soft‐sediment habitats, tissue loss by infuanal invertebrates can provide significant energetic input to higher trophic levels, have substantial impacts on individual behavior, growth, and fecundity, and resulting changes in bioturbation rates can secondarily affect community dynamics. The degree to which a community is affected by such sublethal predation depends in part on whether injured individuals can regenerate and on the speed at which they do so. Previously, we demonstrated differences in the rate of anterior segment and palp regeneration by the spionid polychaetes Pygospio elegans and Dipolydora quadrilobata. The current study examined the morphology of the anterior segment and palp regeneration in these species using scanning electron microscopy (SEM) and indirect immunohistochemistry with confocal laser scanning microscopy at 3, 6, 9, and 12 d post‐ablation. Antibodies for acetylated α‐tubulin and the neural tetrapeptide FMRFamide were used to label the regenerating nervous system. SEM revealed that the morphology of anterior tissue regeneration was similar for both species, but the ciliated food groove tended to form sooner on palps in P. elegans than on those of D. quadrilobata. In both species, palp regeneration and ciliated food groove formation were faster when only palps were removed. A shortened ciliated food groove is likely to reduce particle contact and transport efficiency in suspension and deposit feeding. Regenerating palp nerves were initially visible at 3 d following ablation of palps only, but at 6 d following ablation of five anterior segments. Following ablation of anterior segments, the regenerating nervous system was largely complete by 9 d, nuchal organs were innervated by 6 d, and processes of palp sensory cells were visible at 12 d. Contact chemoreception by sensory cells on the palps may be diminished during the early stages of regeneration, but chemoreception of waterborne cues via the nuchal organ should not.     

桑天牛头部附器感器的扫描电镜观察

利用扫描电镜观测桑天牛Apriona germari(Hope)成虫的触角、下颚须和下唇须上感器的分布及超微结构。结果表明,雌、雄桑天牛触角上共存在6种感器,即毛形感器、锥形感器、刺形感器、芽形感器、鳞形感器和棒形感器,其中锥形感器分5种亚型,刺形感器分2种亚型,且部分感器在雌雄成虫触角上的分布模式及数量存在差异,如棒形感器及角锥形感器丛模式仅在雄虫触角上发现,而雌虫触角上的细锥形感器和耳锥形感器多于雄虫,芽形感器少于雄虫;下颚须和下唇须存在5种感器,即毛形感器、刺形感器、末梢锥形感器、钟形感器和隙缝感器,各种感器在雌、雄天牛下颚须和下唇须上的分布和数量无明显的区别。     

Maxillary palp glomeruli and ipsilateral projections in the antennal lobe of<Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

The antennal lobe was examined by Golgi-silver impregnation to differentiate the glomeruli depending on the source and types of inputs. Thirty-five of the 43 ‘identified’ olfactory glomeruli were Golgi-silver impregnated in the present study. Seven glomeruli compared to three, reported previously, were found to be targets of maxillary palp chemosensory neurons. These include glomeruli VA3, VC2, VM5, VA7m/VA7l of the ventral antennal lobe and DC2, DC3, DM5 of the dorsal antennal lobe. The number of glomeruli receiving the maxillary palp sensory projections tallies with the number ofDrosophila olfactory receptors (seven) reported to be expressed exclusively in the maxillary palp. Twenty-eight Golgi-impregnated glomeruli were found to receive input from the antennal nerve. The ratio of glomeruli serving the maxillary palp to those serving the antenna (∼1:5) matches with the ratio ofDrosophila olfactory receptors expressed in these two olfactory organs respectively. In addition to glomerulus V, glomeruli VP1-3, VL1, VL2a/2p and VC3m/3l were found to receive ipsilateral projections. Thus, additional ipsilateral glomeruli have been identified.     

Olfactory physiology in the Drosophila antenna and maxillary palp: acj6 distinguishes two classes of odorant pathways.

This article provides characterization of the electrical response to odorants in the Drosophila antenna and provides physiological evidence that a second organ, the maxillary palp, also has olfactory function in Drosophila. The acj6 mutation, previously isolated by virtue of defective olfactory behavior, affects olfactory physiology in the maxillary palp as well as in the antenna. Interestingly, abnormal chemosensory jump 6 (acj6) reduces response in the maxillary palp to all odorants tested except benzaldehyde (odor of almond), as if response to benzaldehyde is mediated through a different type of odorant pathway from the other odorants. In other experiments, different parts of the antenna are shown to differ with respect to odorant sensitivity. Evidence is also provided that antennal response to odorants varies with age, and that odorants differ in their age dependence.     

Analysis of Drosophila proboscipedia mutant alleles.

Proboscipedia (PB) is a HOX protein required for adult maxillary palp and proboscis formation. To identify domains of PB important for function, 21 pb point mutant alleles were sequenced. Twelve pb alleles had DNA sequence changes that encode an altered PB protein product. The DNA sequence changes of these 12 alleles fell into 2 categories: missense alleles that effect the PB homeodomain (HD), and nonsense or frameshift alleles that result in C-terminal truncations of the PB protein. The phenotypic analysis of the pb homeobox missense alleles suggests that the PB HD is required for maxillary palp and proboscis development and pb - Sex combs reduced (Scr) genetic interaction. The phenotypic analysis of the pb nonsense or frameshift alleles suggests that the C-terminus is an important region required for maxillary palp and proboscis development and pb-Scr genetic interaction. PB and SCR do not interact directly with one another in a co-immunoprecipitation assay and in a yeast two-hybrid analysis, which suggests the pb-Scr genetic interaction is not mediated by a direct interaction between PB and SCR.     

Comparative morphology of sensilla on antenna,maxillary palp and labial palp of larvae of white‐spotted and yellow‐spotted Asian long‐horned beetle,Anoplophora glabripennis Motschulsky (Coleoptera: Cerambycidae)

The Asian long‐horned beetle (ALB) is one of the most important wood‐boring insects worldwide that damages broad‐leaved trees, primarily poplar, willow, elm and maple. Based on the color of the spots on the elytra, the beetles are separated into white‐spotted (ALB‐W) and yellow‐spotted (ALB‐Y) Asian long‐horned beetles. In order to clarify the morphology of sensilla on antenna, maxillary palp and labial palp of ALB‐W and ALB‐Y larvae, we studied the typology, morphology, number and distribution of the sensilla by scanning electron microscopy. The results showed that: (i) the antennae of two biotypes had five types of sensilla, including three types of sensilla basiconica (b.) and two types of sensilla twig basiconica (s.tb); numbers of b.1, b.2, b.3 and s.tb1 on antenna were not significantly different (P > 0.05) between two biotypes, and the numbers of s.tb2 were significantly different (P < 0.05); (ii) the maxillary palp of two biotypes had four types of sensilla, including sensilla styloconica (st.), two types of s.tb and digitiform sensilla (ds.); the numbers of st. and ds. on the maxillary palp were not significantly different (P > 0.05) between two biotypes, and the numbers of s.tb1 and s.tb2 were significantly different (P < 0.05); (iii) the labial palp of two biotypes had four types of sensilla, including b., st. and two types of s.tb, and the numbers of b.3, st., s.tb1 and s.tb2 on the labial palp were not significantly different (P > 0.05) between two biotypes. We discuss the relationships between sensilla and damage caused by the larvae inside the host trees.     

Sexual dimorphism of adult labial palps of the peach fruit moth Carposina sasakii Matsumura (Lepidoptera: Carposinidae) with notes on their sensilla

The labial palps and their sensilla of the peach fruit moth Carposina sasakii Matsumura, a serious pest of pome fruits in eastern Asia, were investigated using light microscopy and scanning and transmission electron microscopy. The labial palps are three‐segmented and exhibit distinct sexual dimorphism in length: much longer in the female than in the male. Four types of sensilla were found on the labial palps: campaniform, squamiform, chaetic and flattened sensilla. The campaniform sensilla are present on the first segment alone. The squamiform sensilla are located on all the three segments. The chaetic sensilla are mainly present on the third segment. The flattened sensilla are grooved with wall pores and situated in a labial palp‐pit organ, which is located at the apex of the distal segment of the labial palp. The sexual dimorphism of the labial palp and the labial palp‐pit organ was briefly discussed.     

Chemo-discriminatory neurones in the sub-oesophageal ganglion of Locusta migratoria

The sub-oesophageal ganglion of Locusta migratoria was searched for neurones responsive to stimulation of the maxillary palps using intracellular recording techniques. Two plant stimuli were used: wheat, a host plant and cabbage, an unacceptable non-host plant. The stimuli were presented to the palp as both intact leaf tissue and as droplets of aqueous solutions of plant extracts. All the sampled neurones that responded to stimulation of the palp also responded to simple mechanical stimulation. However, 25% of the neurones exhibited consistent differences in response to the two plants when presented as both leaf tissue and droplets, strongly suggesting that they also received a chemosensory input. These differential responses most commonly took the form of differences in the duration of cell activity and/or variation in the latency of the onset of response. The receptive fields of differentially responding neurones were confined to the maxillary palp, or at most to the maxillary and labial palps.     

The maxillary palp of Drosophila : ultrastructure and physiology depends on the lozenge gene

The ultrastructure and physiology of the maxillary palp of Drosophila melanogaster have been studied in wild-type and lozenge mutants. Olfactory physiology in the maxillary palp is shown to depend upon the lozenge(lz) gene. Reduced response amplitudes were recorded for all odorants tested, and the physiological defect was shown to map to the lz locus. The structure of the maxillary palp sensilla is described by scanning electron microscopy (SEM) at high magnification, initially in the wild-type. A linear arrangement of pores, connected by furrows, was found in one class of sensilla, the basiconic sensilla. In the lz ³ mutant, morphological alterations in the basiconic sensilla and duplications of sensilla are documented by SEM. The correlation of structural abnormalities in the lz sensilla and physiological abnormalities in odorant response are consistent with an olfactory role for the basiconic sensilla of the maxillary palp. Accepted: 10 September 1996     

Localization of norovirus and poliovirus in Pacific oysters

Aims:  To examine the uptake and tissue distribution of norovirus (NoV) and poliovirus (PV) experimentally bioaccumulated in feeding Pacific oysters ( Crassostrea gigas ).
Methods and Results:  Pacific oysters were allowed to bioaccumulated either PV or NoV under tidally synchronized feeding conditions in laboratory tanks. Oysters were then either fixed and paraffin wax embedded prior to localizing virus within tissues by immunohistochemistry (IHC), or they were dissected into digestive tract (stomach, intestine and digestive diverticula), gill and labial palp tissues, and the viral load determined by quantitative RT-PCR. Both PV and NoV immunoreactivities were predominantly found in the lumen and within cells of the digestive tract tissues; however, PV was also found within cells of nondigestive tract tissues, and in the gills and labial palp. Quantitative RT-PCR of tissue extracts corroborate the immunohistochemical data in that the major site for virus localization is the gut, but significant amounts of viral RNA were identified in the gills and labial palp.
Conclusions:  The human enteric viruses, PV and NoV, are readily bioaccumulated by feeding Pacific oysters and that some of the virus is internalized within cells of both digestive and nondigestive tissues.
Significance and Impact of the Study:  Oysters that have been virally contaminated even after depuration (cleaning) in uncontaminated seawater could pose a human health risk if consumed.     

Reproductive barriers between the partially sympatric Colorado and false potato beetles

The partially sympatric Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), and the false potato beetle (FPB), Leptinotarsa juncta (Germar), were shown to possess a series of reproductive barriers that protect species integrity. A strongly stereotyped sequence of courtship behaviour insures that more than 85% of encounters between these congeneric species are terminated before copulation. The courtship behaviour of the FPB, described here for the first time, is similar to that for the CPB. However, the male FPB is more likely to walk off the female FPB and will repeat antennal tapping more frequently than the CPB before moving on to palp tapping and mating. Observations suggest that both species first use antennal tapping for an initial olfactory assessment of the object as a female insect of a given family or species and palp tapping for final sex recognition. If courtship behaviour fails to break up the hybridization pairs, there is no mechanical barrier to mating and sperm transfer takes place. However, there is gametic mortality. The FPB is more fecund than the CPB and seems less dependent than the CPB on multiple matings to reach its full reproductive potential.     

Olfactory physiology in the Drosophila antenna and maxillary palp: acj6 Distinguishes two classes of odorant pathways

This article provides characterization of the electrical response to odorants in the Drosophila antenna and provides physiological evidence that a second organ, the maxillary palp, also has olfactory function in Drosophila. The acj6 mutation, previously isolated by virtue of defective olfactory behavior, affects olfactory physiology in the maxillary palp as well as in the antenna. Interestingly, abnormal chemosensory jump 6 (acj6) reduces response in the maxillary palp to all odorants tested except benzaldehyde (odor of almond), as if response to benzaldehyde is mediated through a different type of odorant pathway from the other odorants. In other experiments, different parts of the antenna are shown to differ with respect to odorant sensitivity. Evidence is also provided that antennal response to odorants varies with age, and that odorants differ in their age dependence. © 1992 John Wiley & Sons, Inc.     

Observations of serotonin and FMRFamide-like immunoreactivity in palp sensory structures and the anterior nervous system of spionid polychaetes

Evidence suggests that ciliated sensory structures on the feeding palps of spionid polychaetes may function as chemoreceptors to modulate deposit-feeding activity. To investigate the probable sensory nature of these ciliated cells, we used immunohistochemistry, epi-fluorescence, and confocal laser scanning microscopy to label and image sensory cells, nerves, and their organization relative to the anterior central nervous system in several spionid polychaete species. Antibodies directed against acetylated alphatubulin were used to label the nervous system and detail the innervation of palp sensory cells in all species. In addition, the distribution of serotonin (5-HT) and FMRFamide-like immunoreactivity was compared in the spionid polychaetes Dipolydora quadrilobata and Pygospio elegans. The distribution of serotonin immunoreactivity was also examined in the palps of Polydora cornuta and Streblospio benedicti. Serotonin immunoreactivity was concentrated in cells underlying the food groove of the palps, in the palp nerves, and in the cerebral ganglion. FMRFamide-like immunoreactivity was associated with the cerebral ganglia, nuchal organs and palp nerves, and also with the perikarya of ciliated sensory cells on the palps.     

Differences in degeneration of the apical scolopidial organ in the labial palp of Lepidoptera during pupal development

Summary The apical scolopidial organ (ASO) in the labial palp of six species from four families of Lepidoptera was studied in pupal and imaginal stages using electron microscopy. The organ houses three sensory units, each of which consists of one sensory cell and two enveloping cells at early pupal stage in all the species studied. The distal part of the ASO is connected with the epidermis of the tip of the labial palp. Proximally it is attached to the primordium of the palpal nerve. The axons of the sensory cells run within this nerve to the central nervous system. There are two main differences in the differentiation of the ASO in the species examined during postembryonic development: (1) the sensory cells of the ASO degenerate at different rates; and (2) the ASO may or may not change its position within the palp. In Pieris brassicae and Pieris napi (Pieridae), all three sensory cells undergo stepwise degeneration. Consequently, no sensory cells are left in the imago in these species. However, in the Rhodogastria sp. (Arctiidae), only one sensory cell of the ASO degenerates during pupal life. Two remain, therefore, in the imaginal stage. Their dendritic outer segments and axons are normal, and their appearance does not differ from that in early pupal life. The same process was also observed in Rhodogastria bubo (Arctiidae), Autographa gamma (Noctuidae) and Aglais urticae (Nymphalidae). In addition to the degeneration of the sensory cells the ASO turns through about 180° in P. brassicae and P. napi so that its tip points to the base of the palp in the imagines of these species.     

Retinoic acid differently affects the formation of palps and surrounding neurons in the ascidian tadpole

The anterior-most surface of the ascidian tadpole larvae is composed of specialized complex structures, including adhesive organs (palps) and the surrounding sensory neurons (RTENs) connected to neurons inside the palps. These are derived from a-line blastomeres by inductive effects from A-line blastomeres. The induction is reported to coordinate the expression of homeobox genes in the anterior epidermis, which can be affected by all- trans retinoic acid (RA). RA treatment also results in failure of the morphological formation of palps. Here we first isolated a gene intensely expressed in the cells of the anterior structure from the time of their lineage restriction, and then found that the RA treatment did not affect the specific gene expression in the presumptive palp cells but did affect that in the RTENs. These results suggest that the palp formation involves at least two different processes, a RA-insensitive cell-type specification process and a RA-sensitive morphogenetic process. RA treatment also affects the morphogenetic process of the palp formation and also disturbs the precise patterning of the surrounding epidermis, which may contribute to the regulation of RTEN development.