STUDIES ON STRIGA SENEGALENSIS II. TRANSLOCATION OF C14-LABELLED PHOTOSYNTHATE,UREA-C14 AND SULPHUR-35 BETWEEN HOST AND PARASITE

Using a tracer technique, the nutritional relationship between Striga senegalensis and its host (Sorghum vulgare) has been studied. Preliminary trials with aqueous eosin dye indicated that a mechanism exists for the passage of watery solutions from host to parasite but not vice versa. Use of tracers like C¹⁴O₂, urea-C¹⁴ and sulphur-35 confirmed that minerals as well as organic compounds are translocated from host to parasite. However, when these tracers were applied to the parasites, translocation of labelled products into the host was insignificant. When C¹⁴O₂ was used to label the photosynthate in Sorghum, the bulk of activity appeared in sucrose, glucose and fructose, part of which was presumably obtained by the parasite. The photosynthetic ability of the green tissues of Striga was confirmed. Thus the damaging effect of Striga on the host appears to be due to removal of considerable quantities of water, minerals and organic compounds from the latter. The pattern of translocation of photosynthates and minerals from host to parasite suggests a possible application of selective, systemic weed-killers by aerial spray on the host leaves for control of the parasite.     

Eimeria odocoilei n. sp. from the Mule Deer Odocoileus h. hemionus in Washington*

SYNOPSIS. Eimeria odocoilei n. sp. is described from feces of a mule deer Odocoileus h. hemionus in Washington. Its oocysts are 26 to 28 by 22 to 26 μ. It is the second species of Eimeria described from this host.     

HYBRIDIZATION STUDIES ON THE HOST RACES OF EUROSTA SOLIDAGINIS: IMPLICATIONS FOR SYMPATRIC SPECIATION

We studied the inheritance of survival ability in host-associated populations of the tephritid fly, Eurosta solidaginis, to test predictions of sympatric speciation models. Eurosta solidaginis induces galls on two species of goldenrod, Solidago altissima and S. gigantea. The host-associated populations have been hypothesized to be host races that originated in sympatry (Craig et al. 1993). We found evidence for disruptive selection for host use, which is a critical assumption of sympatric speciation models. Each host race had higher survival rates on their host plant than on the alternative host. F₁ and backcross hybrids also had lower survival rates than the pure host-race flies on their host plant. Since assortative mating occurs due to host-plant preference (Craig et al. 1993) this would select for divergence in host preference. Low hybrid survival could have been due to strong genetic incompatibilities of the populations or due to host adaptation by each population. Strong genetic incompatibilities would result in poor survival on all host plants, while host adaptation could result in low overall survival with high hybrid survival on some host plants with particularly “benign” environments. High survival of F₁, F₂, and backcross hybrids on some plant genotypes in some years supported the host adaptation hypothesis. F₁ flies mated and oviposited normally and produced viable F₂ and backcross hybrids indicating gene flow is possible between the host races. A few flies developed and emerged on the alternative host plant. This demonstrates that genes necessary to utilize the alternative host exist in both host races. This could have facilitated the origin of one of the populations via a host shift from the ancestral host. The inheritance of survival ability appears to be an autosomal trait. We did not find evidence that survival ability was maternally influenced or sex linked.     

The genusOligolecithus Vercammen-Grandjean (Digenea: Telorchiidae) fromXenopus spp. (Anura: Pipidae), with a description ofO. siluranae n. sp. fromX. tropicalis (Gray) in Ghana

The taxonomy, host range and geographical distribution ofOligolecithus Vercammen-Grandjean, 1960, a genus of telorchiid digeneans fromXenopus spp. in Africa, is reviewed.O. jonkershoekensis Pritchard, 1964 is established as a junior synonym ofO. elianae Vercammen-Grandjean, 1960, andO. siluranae n. sp. is described fromX. tropicalis in Ghana. These two species are differentiated by variations in body length, testicular arrangement and ventral sucker width in proportion to body size.O. elianae occurs inX. laevis laevis from South Africa and Zimbabwe (new locality record),X. l. poweri from Zaire,X. l. victorianus from Zaire, Uganda and Rwanda (new locality record),X. l. bunyoniensis (new host record) from Uganda andX. l. sudanensis from Sudan (new host and locality record). It is also found inX. wittei from Uganda and Zaire andX. vestitus (new host record) from Uganda. The host ofO. siluranae belongs to a separate species group within the genusXenopus from the hosts ofO. elianae; this tropicalis group is phylogenetically isolated, but it also occurs in a different biotype, lowland tropical rain forest, ecologically distinct from the other known host species.     

GENETIC VARIATION IN PLANT-INSECT ASSOCIATIONS: SURVIVAL OF LEPTINOTARSA DECEMLINEATA POPULATIONS ON SOLANUM CAROLINENSE

Populations of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae), from the east coast of the United States differ in their ability to survive on a wild host, Solanum carolinense (Solanaceae), but not on their most important cultivated host, Solanum tuberosum. On the wild host, the North Carolina population survived best, while populations from Virginia, New Jersey, and Connecticut exhibited uniformly low survival. Formal genetic studies of populations from Connecticut and North Carolina demonstrated heritable variation in the ability to survive on S. carolinense both between and within populations; the North Carolina population had the higher heritability for this trait. Overall, there was no genetic variation between populations or within the North Carolina population for survival on S. tuberosum, but such variation existed within the Connecticut population. Hybrids and backcrosses between these two lines all survived at intermediate levels, although survivorship did not appear to be inherited additively. Differences in survival were greater than differences in adult weight at emergence and development time of the survivors. Leptinotarsa decemlineata was first reported from North Carolina less than 100 years ago. The rapid expansion of L. decemlineata's host range in North Carolina is attributed to the poor synchrony between the insect and S. tuberosum compared to more northerly locations. In contrast to the prediction of a strong negative correlation in fitness on different host species, the ability of L. decemlineata to survive on S. carolinense was not correlated with that on S. tuberosum. Adult weight and female development time were significantly positively correlated across hosts. Our results are in accord with most previous studies in which strong negative correlations in fitness of specialized phytophagous insects feeding on different hosts were expected, sought, but not found.     

STUDIES ON THE ONTOGENY OF THE DWARF MISTLETOES,ARCEUTHOBIUM. II. HOMOLOGY OF THE ENDOPHYTIC SYSTEM

Cohen , L. I. (Washington State U., Pullman.) Studies on the ontogeny of the dwarf mistletoes, Arceuthobium. H. Homology of the endophytic system. Amor. Jour. Bot. 50(5): 409–417. Illus. 1963.—Development of the seedling in Arceuthobium, as well as the mode of penetration and infection, is described. The promeristem of the root apex of the seedling, as in the embryo, is composed of 4 zones: (1) a uniseriate layer of apical surface initials; (2) a subapical zone of central initials; (3) a peripheral zone; and (4) a zone of procambial initials. After germination, the seedling grows on the host surface until the root apex is confronted by a spur shoot or by a fragment of raised bark. The root apex becomes attached to the host by means of a massive holdfast. It is the procambial initials which actually invade the host tissue. After penetrating the host, the individual procambium initials proliferate in the cortex, each giving rise to a cortical strand. It was concluded that the endophytic system of Arceuthobium cannot be interpreted in terms of classical concepts of plant homology; it is, in fact, an organ sui generis.     

OBSERVATIONS ON CHYTRIDIACEOUS PARASITES OF PHANEROGAMS. XIV. PHYSODERMA CALAMI

Physoderma calami, a chytrid (Phycomycetes), has not been studied or apparently even collected in Europe since 1895 and has never been recorded in this hemisphere. Material widely distributed in herbaria indicated it was a Physoderma but no details save color, shape, and size of resting spores were known. A study of living material from Vermont indicates resting spore germination occurs by dehiscence of a lid and production of a sporangium with zoospores. The latter may form either an epibiotic or “ephemeral” sporangial stage and zoospores, or an endobiotic one, with extensive polycentric thallus bearing turbinate cells along the rhizoids, and, as outgrowths of these turbinate cells, straw-colored, thick-walled resting spores. The latter stage produces dark-brown spots on infected parts of the host.     

OBSERVATIONS ON CHYTRIDIACEOUS PARASITES OF PHANEROGAMS. VIII. UROPHLYCTIS (PHYSODERMA) PLURIANNULATUS AND U. MAJUS

Sparrow , Frederick K. and Yamunga Lingappa . (U. Michigan, Ann Arbor.) Observations on chytridiaceous parasites of phanerogams. VIII. Urophlyctis (Physoderma) pluriannnlatus and U. majus. Amer. Jour. Bot. 47(3): 202—209. Illus. 1960.—Urophlyctis pluriannulatus, an obligate parasite of Sanicula spp., has an endobiotic phase which is strongly polycentric and produces small crateriform galls on the petioles and blades of the host leaves. The agent accomplishing infection is not known but is probably a zygote. The first cell of the parasite established in the host is the so-called “primary turbinate organ.” This becomes multinucleate, is somewhat pyriform and becomes multicellular by 2 methods: (1) by cleavage into peripheral segments; or (2) by division into cells, each with its own cell wall. Replication of the thallus is accomplished by the production of nucleated outgrowths bearing haustoria which elongate, become ribbon-like, somewhat roughened and lumened, and produce distally turbinate organs of a second order. Tertiary, etc. turbinate organs are produced in like manner. Resting spores usually form at the tip of an extremely short outgrowth from the apex of a turbinate organ. These bear a supra-equatorial crown of 7—10 branched haustoria. Rarely, monocentric thalli are formed, in which a single turbinate organ becomes converted into a resting spore. All nuclear division figures were intranuclear. The fungus produced marked enlargement of infected host cells and their nuclei, and caused division of neighboring cells. As development continues, lysis of the surrounding host walls takes place and a large cavity bearing a dense symplast and numerous host nuclei is formed, within which is the thallus of the parasite. At maturity, all traces of symplast and of fungus, except for resting spores, disappear. Urophlyctis majus, a parasite on leaves of Rumex orbiculatus, hitherto known only from its resting spore stage, has a pattern of development strikingly similar to that of U. pluriannulatus. Here, however, turbinate cells only form peripheral segments. Furthermore, the “hyphae” are smooth and without a lumen. Aside from size differences, the mature thallus with resting spores, unbranched (not branched) haustorial tufts, etc. is like that of the Sanicula parasite. The galls produced were compartmentalized, dark red to black, usually surrounded by a reddish zone, and early dropped from the leaf. No undoubted evidence of the epibiotic gametangial phase was found in either species.     

STUDIES ON INDUCED VARIATION IN THE RHIZOBIA. III. HOST RANGE MODIFICATION OF RHIZOBIUM TRIFOLII BY SPONTANEOUS AND RADIATION-INDUCED MUTATION

Schwinghamer , E. A. (Brookhaven Natl. Lab., Upton, New York.) Studies on induced variation in the rhizobia. III. Host range modification of Rhizobium trifolii by spontaneous and radiation-induced mutation. Amer. Jour. Bot. 49(3): 269–277. Illus. 1962.—Mutant strains capable of nodulating pea seedings ineffectively (incapable of nitrogen fixation) have been obtained from 2 antibiotic-resistant marked strains of Rhizobium trifolii which normally do not form nodules on this host. Such variant forms apparently occur spontaneously in these strains at a low frequency which can be significantly increased by irradiation with ultraviolet light, X rays, and fast neutrons. Nodulation of vetch, sweet peas and several varieties of peas by the mutant strains suggests a close parallelism of the extended host range with the range of R. leguminosarum, although nitrogen fixation by the mutants on the new hosts is negligible or absent. The mutant nodules on these hosts also differ from those of the pea strains in slightly smaller size, spherical form, and lighter pink color. Nodule morphology on the homologous host, clover. appears unaltered but a slight loss of effectiveness was noted on red clover. This loss may be attributed partly to a reduction in infective ability since the average number of nodules formed per plant of clover or pea is appreciably lower than for comparable inoculation by strains of nonmutant R. trifolii or R. leguminosarum, respectively. Cultural characteristics of mutant strains resemble those of the nonmutant R. trifolii strains.     

A new species of Acanthobothrium van Beneden, 1850 (Tetraphyllidea: Onchobothriidae) from Pastinachus atrus (Macleay) (Batoidea: Dasyatidae) in Australian waters, with a reassessment of the host associations of Acanthobothrium spp. parasitising Pastinachus spp

A new Category 1 species of Acanthobothrium van Beneden, 1850 is described from the cowtail stingray Pastinachus atrus (Macleay) collected from the Gulf of Carpentaria near Weipa, Queensland, Australia. This species is unique among Acanthobothrium Category 1 species in that it retains gravid proglottids on its strobila. It differs further from the 34 other Category 1 species in total length, proglottid number and testis number. The host identities of other Acanthobothrium species reported from Pastinachus are revised based on recent taxonomic work on rays of this genus. Given the revised host taxonomy, according to which P. atrus is the only member of its genus occurring off Australia, this should be considered to be the fifth species of Acanthobothrium reported from this Australian endemic species.     

Oviposition behavior of Edovum puttleri, reared on two hosts, Leptinotarsa decemlineata and L. texana

Female Edovum puttleri Grissell [Hymenoptera: Eulophidae], reared from eggs of Leptinotarsa decemlineata (Say) or Leptinotarsa texana Schaeffer [Coleoptera: Chrysomelidae], were videotaped as they attacked egg masses of L. decemlineata containing 20 host eggs. We identified 15 components of ovipositional behavior. Parasitoids reared on L. texana attacked and oviposited in significantly more host eggs than did females reared on L. decemlineata. Ethometric analyses of behavioral transitions and a clustering analysis of 34 behavioral parameters showed that females reared on L. texana attacked the host egg mass in a different manner than those reared from L. decemlineata. It was concluded that differences were associated with the host species upon which they were reared. Contrary to previous reports, mortality of unparasitized hosts was caused by an ovipositor probe of short duration, which was not related to host-feeding.     

STUDIES ON THE LIFE CYCLE AND TAXONOMY OF LIGNIERA VERRUCOSA

Miller , Charles E. (A. and M. College of Texas, College Station.) Studies on the life cycle and taxonomy of Ligniera verrucosa. Amer. Jour. Bot. 46(10): 725–729. Illus. 1959.—A study of the roots of Veronica persica Poir. and V. hederaefolia L. plants infected with Sorosphaera veronicae Schroeter revealed intracellular cystosori and zoosporangial sori of Ligniera verrucosa. The zoosporangial phase of this species has been heretofore unknown. The plasmodia of L. verrucosa occur in root hairs, and other epidermal and sub-epidermal cells of the roots. Zoosporangial and cystosoral plasmodia are indistinguishable until cleavage has started. It is thought that plasmodia produced during early infection develop into zoosporangia, while those produced later develop into resting spores. Zoospores discharged from zoosporangia may reinfect host cells developing there into zoosporangial or cystosoral plasmodia. No evidence for any sexual process was observed. The spherical zoosporangia making up a single zoosporangial sorus may be interconnected; a single discharge pore may serve to liberate zoospores from different zoosporangia. In the Plasmodiophorales the classical basis for generic distinction has been the arrangement of the resting spores in the sorus. Ligniera, because of the supposedly uncharacteristic nature of its cystosori, has been suggested as a host-variety of Sorosphaera. A comparative study of the cystosori and zoosporangia of Ligniera and Sorosphaera growing in a single host has led to the conclusion that these genera should be considered distinct.     

NORTH CAROLINA MARINE ALGAE. IX. ONSLOWIA ENDOPHYTICA GEN. ET SP. NOV. (PHAEOPHYTA,SPHACELARIALES) AND NOTES ON OTHER NEW RECORDS FOR NORTH CAROLINA1

Four benthic algae are reported here for the first time in the North Carolina flora. The new brown algal genus and species, Onslowia endophytica Searles, is described as an endophyte of Halymenia floridana from the North Carolina continental shelf. New records of Boodleopsis pusilla and Naccaria corymbosa from North Carolina constitute range extensions of these tropical species on the American coast north from Florida. Blastophysa rhizopus, an endophyte and epiphyte known from the North Atlantic coast of Europe and America as well as the Caribbean is reported from North Carolina for the first time and in a new host, Predaea feldmannii.     

GENETIC CONSTRAINTS ON MACROEVOLUTION: THE EVOLUTION OF HOST AFFILIATION IN THE LEAF BEETLE GENUS OPHRAELLA

We hypothesize that the evolution of an ecologically important character, the host associations of specialized phytophagous insects, has been influenced by limitations on genetic variation. Using as a historical framework a phylogenetic reconstruction of the history of host associations in the beetle genus Ophraella (Chrysomelidae), we have employed quantitative-genetic methods to screen four species for genetic variation in larval survival, oviposition (in one species only), and feeding responses to their congeners' host plants, in the Asteraceae. We here report results of studies of one species and evaluate the results from all four. Analysis of half-sib/full-sib families and of progenies of wild females of O. notulata, a specialist on Iva (Ambrosiinae), provided evidence of genetic variation in larval consumption of five of six test plants and in adult consumption of four of six. Larval mortality was complete on five plants; only on Ambrosia, a close relative of the natural host, was there appreciable, and genetically variable, survival. Oviposition on Ambrosia showed marginally significant evidence of genetic variation; a more distantly related plant elicited no oviposition at all. In compiling results from four Ophraella species, reported in this and two other papers, we found no evidence of genetic variation in 18 of 39 tests of feeding responses and 14 of 16 tests of larval survival on congeners' hosts. This result is consistent with the hypothesis that absence or paucity of genetic variation may constrain or at least bias the evolution of host associations. The lower incidence of genetic variation in survival than in feeding behavior may imply, according to recent models, that avoidance is a more common evolutionary response to novel plants than adaptation. The usually great disparity between mean performance on congeners' hosts and the species' natural hosts, and an almost complete lack of evidence for negative genetic correlations, argue against the likelihood that speciation has occurred by sympatric host shift. The presence versus apparent absence of genetic variation in consumption was correlated with the propinquity of relationship between the beetle species tested and the species that normally feeds on the test plant, suggesting that the history of host shifts in Ophraella has been guided in part by restrictions on genetic variation. It was also correlated with the propinquity of relationship between a test plant and the beetle's natural host. The contributions of plant relationships and insect relationships, themselves correlated in part, to the pattern of genetic variation, are not readily distinguishable, but together accord with phylogenetic evidence that these and other phytophagous insects adapt most readily to related plants. In this instance, therefore, the macroevolution of an ecologically important character appears to have been influenced by genetic constraints. We hypothesize that absence of the structural prerequisites for genetic variation in complex characters may affect genetic variation and the trajectory of evolution.     

ALGAE FROM CABO FRIO UPWELLING AREA. 2. GELIDIOCOLAX PUSTULATA (GELIDIACEAE,RHODOPHYTA): AN UNUSUAL NEW PUTATIVE PARASITIC SPECIES1

A new species of Gelidiocolax Gardner, G. pustulata Oliveira and Yoneshigue, is described in the tropical western Atlantic from Brazil. The species usually grows on the basal portion of the main axis of Pterocladia capillacea (Gmelin) Bornet et Thuret. Abundant material was collected mainly from November to March at Cabo Frio Island, in the northeast part of the State of Rio de Janeiro, a marine area well known for its upwelling. Infection by the putative parasite seems to damage the host tissue, stimulating the development of a “gall-like” structure that leads to the outgrowth of adventitious branches. The new species has the vegetative features and reproductive structures of the genus Gelidiocolax. It can be distinguished from the other Gelidiocolax species mainly on the basis of its position on the host, size of pustula, the tetrasporangia and the development of spermatangia. Studies of this new taxon support the placement of Gelidiocolax in the Gelidiaceae and not the Choreocolacaceae, as has been suggested in the literature.     

A comparative study of the egg-laying behaviour and larval development of Pieris rapae L. and P. brassicae L. on the same host plants

Summary Pieris rapae and P. brassicae feed on the same host plants and have synchronized seasons. P. brassicae, whose larvae are twice the size of P. rapae, lays eggs in clusters of 40–100 eggs whereas P. rapae lays single eggs. In this paper we examine how egg clustering may be advantageous for P. brassicae. The larval development of each species was studied, and found not to differ significantly. P. brassicae larvae were observed to migrate from their host plant after defoliating it. A comparison of the efficiency of host plant utilization by the two pierid species was undertaken by measuring the effect of larval feeding on the growth of their host plants (kale and brussel sprouts). The results show that egg clustering is advantageous for larval fitness in terms of host resource exploitation, and we suggest that P. brassicae is adapted for ovipositing on clumped vegetation, while P. rapae is selected for exploiting isolated plants.     

COMPARATIVE DEVELOPMENT OF THE RED ALGAL PARASITES BOSTRYCHIOCOLAX AUSTRALIS GEN. ET SP. NOV. AND DAWSONIOCOLAX BOSTRYCHIAE (CHOREOCOLACACEAE,RHODOPHYTA)1

The development of two red algal parasites was examined in laboratory culture. The red algal parasite Bostrychiocolax australis gen. et sp. nov., from Australia, originally misidentified as Dawsoniocolax bostrychiae (Joly et Yamaguishi-Tomita) Joly et Yamaguishi-Tomita, completes its life history in 6 weeks on its host Bostrychia radicans (Montagne) Montagne. Initially the spores divide to form a small lenticular cell, and then a germ tube grows from the opposite pole. Upon contact with the host cuticle, the germ tube penetrates the host cell wall. The tip of the germ tube expands, and the spore cytoplasm moves into this expanded tip. The expanded germ tube tip becomes the first endophytic cell from which a parasite cell is cut off that fuses with a host tier cell. The nuclei of this infected host cell enlarge. As parasite development continues, other host-parasite cell fusions are formed, transferring more parasite nuclei into host cells. The erumpent colorless multicellular parasite develops externally on the host, and reproductive structures are visible within 2 weeks. Tetrasporangia are superficial and cruciately or tetra-hedrally divided. Spermatia are formed in clusters. The carpogonial branches are four-celled, and the carpogonium fuses directly with the auxiliary (support) cell. The mature carposporophyte has a large central fusion cell and sympodially branched gonimoblast filaments. Early stages of development differ markedly in Dawsoniocolax bostrychiae from Brazil. Upon contact with the host, the spore undergoes a nearly equal division, and a germ tube elongates from the more basal of the two spore cells, penetrates the host cell wall, and fuses with a host tier cell. Subsequent development involves enlargement of the original spore body and division to form a multicellular cushion, from which descending rhizoidal filaments form that fuse with underlying host cells. This radically different development is in marked contrast to the final reproductive morphology, which is similar to B. australis and has lead to taxonomic confusion between these two entities. The different spore germination patterns and early germ-ling development of B. australis and D. bostrychiae warrant the formation of a new genus for the Australian parasite.     

SOME LABOULBENIACEAE (ASCOMYCETES) ON INSECTS FROM INDIA AND INDONESIA

Batra, Suzanne W. T. (U. Kansas, Lawrence.) Some Laboulbeniaceac (Ascomycetes) on insects from India and Indonesia. Amer. Jour. Bot. 50 (10): 986–992. Illus. 1963.—Laboulbenia camponoti, L. olitskyi, L. styphlomeri and Stigmatomyces scatellae are described as new. Developmental stages of the monoecious species, L. camponoti, on ants are illustrated. It appears to be closely related to the dioecious species, L. formicarum. New host and locality records are given for L. vulgaris, L. flagellata and S. hylemyiae.     

Oviposition vs. offspring fitness in Aphidius colemani parasitizing different aphid species

We measured the acceptance and suitability of four aphid species [Aphis gossypii Glover, Myzus persicae (Sulzer), Rhopalosiphum padi (L.), and Schizaphis graminum (Rondani)] (Homoptera: Aphididae) for the parasitoid Aphidius colemani Viereck (Hymenoptera: Braconidae). Female parasitoids parasitized fewer R. padi than the other three aphid species, and fewer offspring successfully completed development in R. padi than in the other three host species. Sex ratios of emerging adults were more male‐biased from R. padi than from the other three aphid species, suggesting that R. padi is a poor quality host for this population of A. colemani. Ovipositing A. colemani encountered R. padi at a slower rate, spent more time handling R. padi, and parasitoid offspring died at a higher rate in R. padi compared to A. gossypii. Our results show that oviposition behavior and offspring performance are correlated. In each experiment, we tested the effect of the host species in which the parasitoids developed (parental host) on the number of hosts attacked, the proportion of each host species accepted for oviposition and the survival of progeny. Parental host affected maternal body size and, through its effect on body size, the rate of encounter with hosts. Other than this, parental host species did not affect parasitism.     

Attraction of the cerambycid beetles Tetropium gabrieli,T. castaneum and T. fuscum to pheromones and host tree volatiles

1. Tetropium gabrieli is native to the European Alps where it breeds in European larch and may be an important pest during drought periods by killing trees. It has spread to larch plantations in several European countries including Sweden.
2. In trapping studies conducted in Sweden, we tested whether T. gabrieli was attracted to E-fuscumol, E,Z-fuscumol, E,Z-fuscumol acetate and the host volatile combination of α-pinene plus ethanol. We also compared its response with those of the native congeners, T. fuscum and T. castaneum.
3. All three Tetropium species were caught in significantly higher numbers in traps baited with E-fuscumol plus host volatiles than in traps baited with host volatiles alone or in unbaited traps.
4. There was no difference in catch of any Tetropium species between traps baited with E-fuscumol plus host volatiles versus traps baited with E,Z-fuscumol plus host volatiles, but the latter treatment caught more T. fuscum and T. castaneum than did E,Z-fuscumol acetate plus host volatiles.
5. The addition of E-fuscumol to host volatile-baited traps significantly reduced mean catch of T. gabrieli, significantly increased mean catch of T. castaneum, and had no significant effect on catch of T. fuscum. Mean catch of all three species was significantly greater in traps baited with E-fuscumol alone than in traps baited with host volatiles alone.
6. All three species were caught from May to August. The median date of captures was about 2 weeks earlier for T. fuscum compared with the other two species.