Sorting Areas Research Articles

Relative Abundance of Ambrosia Beetles in an Old-Growth Western Hemlock/Pacific Silver Fir Forest and Adjacent Harvesting Areas

Abstract Semiochemical-baited multiple-funnel traps were set out in two new logging areas and in mature forest on northeastern Vancouver Island near Kelsey Bay, British Columbia. The large numbers of ambrosia beetles captured indicated that Trypodendron lineatum and Gnathotrichus sulcatus are distributed along logging rights-of-way as well as in the surrounding forest. Results suggest that logs must be removed as soon as possible after felling in order to minimize degrade of the logs and to prevent the transport of ambrosia beetles from the harvesting areas to dryland sorting areas, booming grounds, and sawmills. West. J. Appl. For. 4(4):132-136, October 1989.

The stomach in the bivalvia

The stomach in the bivalvia

The functional morphology of Sinonovacula constricta with a discussion on the taxonomic status of the Novaculininae (Bivalvia).

Sinonovacula constricta is representative of two genera of deep burrowing bivalves hitherto placed in the Novaculininae of the Tellinacea. This species, widely cultured in China, has not previously been critically examined. Aspects of its anatomy show that it should more properly be placed in the Solenacea. The presently accepted classification of this superfamily suggests that it should be placed close to Pharella in the Cultellidae but it is clear that the group requires more detailed re‐examination.Sinonovacula is somewhat posteriorly elongate with long separate siphons. The anterior pedal gape acts as a valve to the piston‐like foot enabling rapid reburrowing to occur. Sensory tentacles around the pedal gape respond to mechanical disturbance and water can be squirted from the gape to, presumably, flush away the source of irritation. Modifications of this kind are rare in the Bivalvia.The anatomy of Sinonovacula is described and related to its life style as a suspension feeder in soft intertidal muds. The ciliary currents of the mantle cavity are powerful, the labial palps in particular being large as compared with the relatively small ctenidia. The stomach is adapted for dealing with large amounts of food, though the sorting areas are not extensive; principal sorting is clearly the function of the labial palps. The style sac and mid‐gut are separate (unlike the conjoined style sac and mid gut of the Tellinacea), and ensure separation of the style from the sediment loaded mid gut.In many ways Sinonovacula foreshadows the highly modified true razor shells and conditions in these bivalves can be accounted for by further posterior elongation of a bivalve essentially similar to Sinonovacula.

The functional and adaptive morphology of the deep-sea species of the Arcacea (Mollusca: Bivalvia) from the Atlantic

Species of two genera,BathyarcaKobelt (1891) andBentharcaVerrill and Bush (1898), occur beyond the shelf-slope break of the continental margins of the Atlantic. Little is known of these species and descriptions of the morphology ofBathyarca glacialis, B. pectunculoides, B. inaequisculpta, B. corpulenta, Bentharca nodulosaandB. asperulaare given. The species ofBathyarcashow a progression in form from an epibyssate nestling habit to an infaunal endobyssate habit. Correlated with this are various morphological changes. Thus the byssus, which is short and stout and controlled by strong retractor muscles in the epibyssateB. glacialis, is long and slender with weak associated musculature in endobyssateB. inaequisculpta. The mantle/shell form is increasingly heteromyarian in character in deeper-living species, with the increasing development of mantle flaps and muscles of the gill axis. In contrast, the species ofBentharcahave largely retained their epibyssate habit. Their morphology is conservative and differs little from shallow-water arcids. Features are found in both genera that are related to the small quantity of suspended food present in the deep sea. These include the lack of glands in mantle tissue, the reduced palps and lack of sorting areas in the stomach. InBathyarca corpulentaalone the (body biomass): (shell volume) ratio is reduced.

An Operational Pheromone-Based Suppression Program for an Ambrosia Beetle, Gnathotrichus sulcatus, in a Commercial Sawmill12

Sticky-traps baited continuously with racemic sulcatol (6-methyl-5-hepten-2-01) set out in 5 locations in a commercial sawmill in 1976, captured 42,907 Gnathotrichus sulcatus (LeConte), an estimated 65.1% of the total population. Peak flights occurred in the 1st wk of May and Sept. Highest attack rates on lumber occurred also at these times and for the following 3 wk as attacking beetles apparently set up competitive natural sources of secondary attraction. Major factors associated with higher beetle catches were temperature, mill log inventory, and lumber inventory. Numbers of attacks on lumber were also positively correlated with the sum of the attacks for the previous 3 wk. Percentage suppression of beetles was highest in the warmer summer months when inflight populations were low. Vertical distribution of beetles on traps was directly related to height of the pheromone release system. The suppression traps required less than one man-day/month for maintenance, and offer an effective alternative to the use of conventional insecticides. The mass trapping technique could be readily adapted for dryland log sorting areas to help prevent the build up of pest populations of G. sulcatus.

ATTACK BY GNATHOTRICHUS SULCATUS (COLEOPTERA: SCOLYTIDAE) ON STUMPS AND FELLED TREES BAITED WITH SULCATOL AND ETHANOL

AbstractEthanol and sulcatol (6-methyl-5-hepten-2-ol), primary attractant and population aggregation pheromone, respectively, for Gnathotrichus sulcatus, were deployed alone or in combination on stumps and felled trees in the University of British Columbia Research Forest, Maple Ridge, B.C. On 18 April 1974, four Douglas-fir trees were felled at each of three locations, and four western hemlock trees were felled at each of three other locations. Felled trees and their respective stumps were baited on 26 April. Attacks by G. sulcatus and bark beetles were recorded at weekly intervals until 25 October. G. sulcatus attacks increased rapidly, reaching a maximum in June and July, followed by a steady decrease to October. Attacks by Dendroctonus pseudotsugae, Pseudohylesinus nebulosus, and P. tsugae showed characteristic seasonal trends, but were not correlated to any of the treatments. Over half the G. sulcatus attacks were on stumps, in which attack densities reached 683.5/m2. The greatest numbers of attacks were on stumps and logs baited with sulcatol or sulcatol plus ethanol. There was a significant interaction between sulcatol and ethanol on Douglas-fir but not on western hemlock. Significantly more G. sulcatus attacked ethanol-baited western hemlock stumps and logs than unbaited controls. However, there was no difference between the level of attack on ethanol-baited Douglas-fir and the controls. The role of ethanol is hypothesized to be more of a boring stimulant than a major attractant. Stumps baited with sulcatol and then treated with ethanolic solutions of systemic insecticide could be used to trap and kill field populations, thus reducing numbers of G. sulcatus being transported to log-booming grounds, dryland sorting areas, and sawmills.

Umbonium vestiarium, a filter‐feeding trochid

U. vestiarium, a dominant species on the seaward side of sand flats at the mouth of the River Vellar, S. India, collects food by filtering the palliai stream of water as it glides over the surface of the sand or is buried except for its tentacles, eye stalks and siphons. It may remain stationary or creep when buried, but feeds only when conditions are quiet. Inhalant and exhalant siphons are formed by folding of the neck lobes of the epipodium; elsewhere the entrance to the mantle cavity is blocked by the head. The inhalant current is filtered by siphonal tentacles and then passes over the osphradium which encircles the base of the siphon. The gill is monopectinate with the axis, which is fused to the mantle throughout its length, shifted to the right so that the prebranchial chamber of the mantle cavity is large; it can be reduced by muscles in the mantle skirt and the gill displaced from the feeding position. The gill filaments are filiform and elongated and their tips overarch a food groove, except anteriorly. Secretion for trapping food is produced by an endostyle and hypobranchial glands. The food cord, formed by the combined action of cilia on the tips of the filaments and dorsal body wall, is directed to the lateral margin of the right eye stalk. It passes beneath the stalk towards the mouth which is at the end of a very small tubular snout hidden between the bases of the siphons. When food in suspension is scarce, organic matter is collected from the substratum, its supply to the vicinity of the mouth being regulated by the activity of the right tentacle and the foot. Odontophore, salivary and oesophageal glands are reduced. There is no crystalline style; the stomach has large sorting areas and a small gastric shield. A valve prevents entry of paniculate matter to the single duct of the digestive gland. Modifications of shell and foot facilitate burrowing in the uncompacted sand and enable the snail to resist displacement when conditions are adverse. The animal moves easily through soft substrata, but with difficulty over a hard one.

II.—The Neogastropod Stomach, with Notes on the Digestive Diverticula and Intestine

SynopsisOn the basis of Graham's (1949) work, the stomach of the neogastropods is currently regarded as a secondarily simplified structure exhibiting loss of the cæcum, abbreviation of the major typhlosole and intestinal groove, anterior migration of the opening of the œsophagus, loss of the sorting areas, and in the muricids, of the gastric shield. The present investigations, however, reveal that the stomachs of, at any rate, some neogastropods are less simplified than has been realized. There are well developed typhlosoles, an intestinal groove, gastric shield, and sorting areas resembling those of primitive gastropods.

The structure and function of the stomach in bivalve molluscs

The structure and function of the stomachs of nine bivalves are examined. These animals belong to the Gastrotetartika, Gastrotriteia, and Gastropempta, the three orders of the Polysyringia, a new sub‐class of the Bivalvia suggested by Purchon (1960a). It is found that in all three orders there are common ciliary tracts and grooves. For example, tracts are always found in association with the duct openings, and a distinction between the right duct tract and the posterior sorting area is drawn. Another tract which is a constant feature of these stomachs, but which has not been noted before, is the antero‐dorsal tract. A generalized polysyringian stomach is constructed. All the stomachs examined function similarly, there being set up in the lumina circulating currents of the gastric fluid. In general, large particles and masses of particles are recirculated until they are broken down, and small heavy particles are rejected by the sorting areas, of which three main types are described. Light particles in suspension in the stomach fluid are carried by the circulating current to the vicinity of the opening of the ducts of the digestive diverticula.The form of the primitive polysyringian stomach and the evolution of sorting areas are postulated. Possible steps in the evolution of the gastropemptan stomach through the gastrotetartikan form are suggested. The function of the appendix is that of a temporary store for large, heavy particles which escape the pallial sortingjnechanisms. It is noted that this organ occurs in all three orders of the Polysyringia.

On the basic form and adaptations to habitat in the Lucinacea (Eulamellibranchia)

The Lucinacea (Eulamellibranchia) have been studied and particular attention has been paid to the feeding, respiratory and cleansing currents and their relation to the morphology and habits of the group. The Lucinacea comprise three families, the Ungulinidae, Thyasiridae and Lucinidae, and living specimens of thirteen species were studied; namely,Diplodonta rotundata, D. punctata, D. aspera(Ungulinidae);Thyasira Jlexuosa(Thyasiridae);Lucina pennsylvanica, L. chrysostoma. Codakia orbicularis, C. orbiculata, C. costata, Loripes lucinalis, Phacoides borealis, Myrtea spinifera, Divaricella quadrisulcata(Lucinidae). These species occur on a variety of substrata ranging from coarse sand to fine mud particularly where the associated fauna is sparse. Shallow-water species are often found among the roots of marine grasses such asZosteraandThalassia. The mantle is described, notably the extensive glandular tissue of the mantle margin, also the ‘mantle gills’ and the unique form of the exhalent siphon both of which are confined to the Lucinidae. The great development of the glandular tissue at the mantle margin is probably related to large quantities of sediment entering the mantle cavity. While many of the gland cells close to the epithelium show typical basiphilic reactions of mucus-secreting cells, those further from the epithelium show marked eosinophilic-staining reactions. The only visible difference between the cells appears to be a difference in cytoplasmic granule size, those to the inside possessing the larger granules. ‘ Mantle gills ’ consist of convoluted folds of the inner mantle epithelium close to the anterior adductor muscle. They occur in Codakia orbicularis and Lucina pennsylvanica. The folds are parallel to the direction of the ciliary currents. There are no gland cells, but there are many blood vessels below the folds and the latter are probably concerned with respiration. The exhalent siphon in the Lucinidae does not contract into a pallial sinus, but turns inside out and lies in the suprabranchial cavity, a method that appears to be unique. The anterior adductor muscle is elongate and the greater part of it lies ventral and posterior to the mouth. Its surface epithelium is ciliated and acts as a sorting area for particles entering by the anterior inhalent tube. The Ungulinidae are least specialized in this respect and the Lucinidae the most specialized. The variations of the ciliary currents on the body are described. The foot is highly specialized, it is used in burrowing and also forms the anterior inhalent tube. It is typically long and vermiform often with a distinct tip. In the Lucinidae the heel is well developed and may be distinct from the vermiform portion. The latter is chiefly concerned with tube formation and the heel with digging. In some species the foot can extend to more than ten times the length of the shell. The tip of the foot is profusely supplied with glands which supply material for tube formation. An account of this and of burrowing is given. The morphology and ciliary mechanisms of the gills are described. In the Ungulinidae and Thyasiridae the outer demibranch is reduced and in the Lucinidae this demibranch is absent. All the species studied have homorhabdic gills. In the Thyasiridae and Lucinidae development of the subfilamentar tissue gives a fleshy appearance to the gills. The palps show progressive reduction in size in the three families. The Ungulinidae and the Thyasiridae retain the typical ciliated folds. The palps of the Lucinidae are slight enlargements of the walls of the oral groove. Vestiges of not more than three folds remain which are still capable of a limited amount of sorting. The stomach and digestive diverticula are described; the sorting mechanisms are progressively reduced. They are least reduced in the Ungulinidae being essentially the same as those of other Eulamellibranchia. In the Thyasiridae and the Lucinidae there is reduction in the sorting areas of the stomach and the number of ducts of the digestive diverticula. The resulting simplification of the stomach emphasizes the importance of (1) the acceptance tract, (2) the typhlosoles, (3) the left caecum, (4) the dorsal groove, and (5) the tooth on the gastric shield. The digestive diverticula of the Ungulinidae are of the typical eulamellibranch pattern, those of the Lucinidae and Thyasiridae have much larger ducts and tubules, both in the size of the lumen and of the cells. Tubules only are present in the Thyasiridae. The excretory, circulatory and nervous systems do not differ significantly from those of other Eulamellibranchia. The evolution of the group is discussed particularly in relation to the anterior inhalent current and the correlated reduction in sorting mechanisms of the gills, palps and stomach, together with the development of the anterior adductor muscle, foot and exhalent siphon.