The Life-History of Pineus pinifoliae (Fitch) (Homoptera: Phylloxeridae) and its Effect on White Pine

1950 ◽  
Vol 82 (6) ◽  
pp. 117-123 ◽  
Author(s):  
R. E. Balch ◽  
G. R. Underwood

Pineus pinifoliae (Fitch) belongs to the Adelginae, a group characterized by unusually complex life-cycles. The typical species have at least five distinct forms, one bi-sexual and the others parthenogenetic. They alternate between two coniferous hosts, one of which is always a species of spruce (Picea). Galls are formed on spruce by a modification of the growth of the new shoot.The life-history of P. pinifoliae is only partially known. Patch has reported on observations in Maine which showed that the gall-making form flew from “black spruce” to the needles of white pine and that its offspring settled on the new shoots. She also described a morphologically similar winged form which developed on white-pine shoots and which she believed to be the return migrants. Annand made similar observations in Oregon and gave careful descriptions of three forms: the fundatrix, the gallicola migrans, and the exulis.

2021 ◽  
Author(s):  
Dustin T. Dial ◽  
Kathryn M. Weglarz ◽  
Akintunde O. Aremu ◽  
Nathan P. Havill ◽  
Taylor A. Pearson ◽  
...  

AbstractMany plant-sap-feeding insects have maintained a single, obligate, nutritional symbiont over the long history of their lineage. This senior symbiont may be joined by one or more junior symbionts that compensate for gaps in function incurred through genome-degradative forces. Adelgids are sap-sucking insects that feed solely on conifer trees and follow complex life cycles in which the diet fluctuates in nutrient levels. Adelgids are unusual in that both senior and junior symbionts appear to have been replaced repeatedly over their evolutionary history. Genomes can provide clues to understanding symbiont replacements, but only the dual symbionts of hemlock adelgids have been examined thus far. Here, we sequence and compare genomes of four additional dual-symbiont pairs in adelgids. We show that these symbionts are nutritional partners originating from diverse bacterial lineages and exhibiting wide variation in general genome characteristics. Although dual symbionts cooperate to produce nutrients, the balance of contributions varies widely across pairs, and total genome contents reflect a range of ages and degrees of degradation. Most symbionts appear to be in transitional states of genome reduction. Our findings support a hypothesis of periodic symbiont turnover driven by fluctuating selection for nutritional provisioning related to gains and losses of complex life cycles in their hosts.


Ecology ◽  
2012 ◽  
Vol 93 (3) ◽  
pp. 657-667 ◽  
Author(s):  
Benedikt R. Schmidt ◽  
Walter Hödl ◽  
Michael Schaub

Parasitology ◽  
1998 ◽  
Vol 116 (S1) ◽  
pp. S47-S55 ◽  
Author(s):  
J. C. Koella ◽  
P. Agnew ◽  
Y. Michalakis

SummarySeveral recent studies have discussed the interaction of host life-history traits and parasite life cycles. It has been observed that the life-history of a host often changes after infection by a parasite. In some cases, changes of host life-history traits reduce the costs of parasitism and can be interpreted as a form of resistance against the parasite. In other cases, changes of host life-history traits increase the parasite's transmission and can be interpreted as manipulation by the parasite. Alternatively, changes of host's life-history traits can also induce responses in the parasite's life cycle traits. After a brief review of recent studies, we treat in more detail the interaction between the microsporidian parasite Edhazardia aedis and its host, the mosquito Aedes aegypti. We consider the interactions between the host's life-history and parasite's life cycle that help shape the evolutionary ecology of their relationship. In particular, these interactions determine whether the parasite is benign and transmits vertically or is virulent and transmits horizontally.Key words: host-parasite interaction, life-history, life cycle, coevolution.


1985 ◽  
Vol 22 (6) ◽  
pp. 850-871 ◽  
Author(s):  
Svante Björck

Along a 420 km transect in northwestern Ontario, Canada, sediments from four lakes were analyzed with respect to lithology, pollen, and macrofossils. Radiocarbon dates show that the region was deglaciated between ca. 11 500 and 8000 years BP, and periods of both rapid ice retreat and readvance influenced the history of Glacial Lake Agassiz. In the south the ice sheet was succeeded by a lengthy interval of park–tundra with stands of spruce, ash, and elm. The ash and elm seem to have disappeared during a suggested cool period (11 100–10 200 years BP). Farther north the park–tundra phase lasted not more than 50–100 years after ca. 10 200 years BP before boreal trees dominated. The climatic change around 10 200 years BP permitted the very rapid migration of spruce, larch, birch, and jack or red pine into northwestern Ontario from northern Minnesota. The migration routes for Pinus strobus (white pine), Alnus rugosa, and A. crispa were divided, however: one from the south (south of Lake Superior) and one from the east-southeast (north of Lake Superior). White pine reached its maximum distribution 6500–6000 years BP, when the limit was probably 150–200 km north of today's. The composition of the boreal forest during the altithermal was only slightly changed, but the influx of presumed prairie pollen reached a peak ca. 8000–7000 years BP. Since then Picea mariana (black spruce) gradually became the dominating tree species.


1974 ◽  
Vol 31 (3) ◽  
pp. 319-325 ◽  
Author(s):  
G. F. Carpenter ◽  
E. L. Mansey ◽  
N. H. F. Watson

In sampling on lakes Ontario, Erie, and Superior during three cruises from spring to fall, and on Lake Huron during eight cruises, Mysis relicta was generally not taken or not abundant in waters less than 25 m in depth. Its abundance appeared to increase with depth at least up to 200 m. Populations appeared to be concentrated in waters 125–200 m deep during summer and more dispersed during spring and fall. Highest numbers were found in Lake Superior, followed by lakes Ontario and Huron. A small localized population was found in the deep eastern part of Lake Erie.Size-frequency distributions from the various cruises on lakes Superior, Huron, and Ontario indicated differences in life cycles of the mysid in the three lakes. In Lake Superior there was one major period of recruitment, from February to July, and the generation time appeared to be 2 yr. In lakes Huron and Ontario recruitment appeared to occur from February to August and to be separated into a winter and a summer period; each of the generations appeared to mature in 18 mo.


2021 ◽  
pp. 19-50
Author(s):  
Paul Schmid-Hempel

Parasites are more numerous than non-parasitic species and have evolved in virtually all groups of organisms, such as viruses, prokaryotes (bacteria), protozoa, fungi, nematodes, flatworms, acantocephalans, annelids, crustaceans, and arthropods (crustacea, mites, ticks, insects). These groups have adapted to the parasitic lifestyle in very many ways. Evolution towards parasitism has also followed different routes. Initial steps such as phoresy, followed by later consumption of the transport host, are plausible evolutionary routes. Alternatively, formerly free-living forms have become commensals before evolving parasitism. Complex life cycles with several hosts evolved by scenarios such as upward (adding a new host upwards in the food chain), downward, or lateral incorporation, driven by the advantage of extending growth phases within hosts and increasing fecundity. Examples are digenea; other parasites have added vectors to their life cycle.


EvoDevo ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Joachim M. Surm ◽  
Yehu Moran

AbstractVenomous animals are a striking example of the convergent evolution of a complex trait. These animals have independently evolved an apparatus that synthesizes, stores, and secretes a mixture of toxic compounds to the target animal through the infliction of a wound. Among these distantly related animals, some can modulate and compartmentalize functionally distinct venoms related to predation and defense. A process to separate distinct venoms can occur within and across complex life cycles as well as more streamlined ontogenies, depending on their life-history requirements. Moreover, the morphological and cellular complexity of the venom apparatus likely facilitates the functional diversity of venom deployed within a given life stage. Intersexual variation of venoms has also evolved further contributing to the massive diversity of toxic compounds characterized in these animals. These changes in the biochemical phenotype of venom can directly affect the fitness of these animals, having important implications in their diet, behavior, and mating biology. In this review, we explore the current literature that is unraveling the temporal dynamics of the venom system that are required by these animals to meet their ecological functions. These recent findings have important consequences in understanding the evolution and development of a convergent complex trait and its organismal and ecological implications.


1998 ◽  
Vol 130 (1) ◽  
pp. 79-90 ◽  
Author(s):  
Peter de Groot

AbstractThe life history of the white pine cone borer, Eucosma tocullionana Heinrich, was studied from 1992 to 1994 in an eastern white pine seed orchard in Ontario. Adults flew from late May to early July, and egg laying commenced in mid-June. Oviposition coincided with the onset of white pine pollen release. Eggs were laid singly or in clusters on cones, with most of the eggs laid on the basal third of the cone. Head capsule measurements indicated five instars. Larvae fed in cones from mid-June to the end of August. Mature larvae exited the cones and dropped to the ground to pupate. The insect is univoltine. Parasitism by the Hymenoptera, Trichogramma and Apanteles, accounted for 5% of the eggs and 1% of the larvae, respectively. About 40% of the larvae died from being entrapped in resin. There were no significant differences in attack rates by E. tocullionana within the tree except in the middle level, where the south quadrant had significantly higher rates than the north quadrant.


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