Life History and Some Habits of the Pine Gall Weevil, Podapion gallicola Riley, in Michigan

1965 ◽  
Vol 97 (9) ◽  
pp. 962-969
Author(s):  
Louis F. Wilson

AbstractThe pine gall weevil has a 3-year life cycle on red pine (Pinus resinosa Ait.) in Michigan. Adults oviposit from June to August, depositing 1 to 10 eggs in a niche chewed in the bark of a branch internode. Larvae first emerge in August, feed as a group toward the cambium, and then radiate out along the xylem. Head capsule measurements from 1585 larvae indicate that there are three larval instars. Gall development begins in June of the second year, shortly after the larvae begin the second instar. The third instar commences in June of the third year. Pupation occurs in May of the fourth season; adult emergence follows in June. Overwintering occurs in the egg stage or in the three larval instars. Adults do not overwinter, and apparently three distinct broods occur in Michigan.

Holzforschung ◽  
2002 ◽  
Vol 56 (4) ◽  
pp. 335-359 ◽  
Author(s):  
P. Oevering ◽  
A.J. Pitman

Summary Pselactus spadix attack of marine timbers was characterised by circular emergence holes 1.48±0.05 mm in diameter and adult tunnels (1.49±0.34 mm) breaking through the wood surface. Larval tunnels measured 0.407–1.892 mm in diameter, initiated from adult tunnels and increased in diameter away from the adult tunnel terminating in frass free pupal chambers (1.6±0.3 mm × 3.5±0.7 mm). Observations of larval tunnel locations indicated oviposition occurred inside the adult tunnels. P. spadix life history was investigated in Scots pine (Pinus sylvestris) heartwood at 22±2 °C and 99±1% r.h. Mean adult longevity was 11.5±6.5 months, with mean post-mating longevity for males (11.7±2.9 months) significantly longer than for females (6.3±1.1 months). Adults of at least 2–3 months old were found mating in galleries, which, with observations of the larval tunnel pattern, indicated P. spadix can complete its life cycle without emerging from wood. Five larval instars were identified by measurement of 1722 head capsule widths and application of Dyar's law. Mean development time from 2nd instar to adult emergence was 70.5±6.9 weeks and pupation took 14.6±5.8 days. Development from 2nd instar to reproductive adult took between 17–20 months, with life cycle approximating 24 months at 22±2 °C and 99±1%


Author(s):  
Alec R. Lackmann ◽  
Malcolm G. Butler

Except for one unconfirmed case, chironomid larvae have been reported to pass through four larval instars between egg and pupal stages. We have observed a fifth larval instar to be a standard life-cycle feature of the podonomine Trichotanypus alaskensis Brundin 1966 in tundra ponds on the Arctic Coastal Plain near Barrow, Alaska. T. alaskensis has a one-year life cycle in these arctic ponds. Adults emerge in June ~2-3 weeks after pond thaw, then mate and oviposit; most newly-hatched larvae reach instar IV by October when pond sediments freeze. Overwintering larvae complete instar IV within a few days of thaw, then molt again to a fifth larval instar. Imaginal discs, normally seen only during instar IV in Chironomidae, develop across both instars IV & V prior to pupation and adult emergence. While monitoring larval development post-thaw in 2014, we noticed freshly-molted T. alaskensis larval exuviae a week or more prior to any pupation by that species. In 2015-16 we reared overwintering instar IV larvae from single pond sources, individually with daily monitoring, through molts to instar V, pupa, and adult. Some overwintering instar II and III larvae were reared as well, but were few in number. During 2016 we also reared T. alaskensis progeny (from eggs) through instar II, thus documenting head capsule size ranges for all five instars in a single pond’s population. Without individual rearings, the fifth larval instar was not readily apparent for two reasons: 1) The molt itself occurs immediately after thaw and is so synchronous it is difficult to discern in daily field samples. 2) The head capsule size increment between instars IV-V is much lower than the ratio predicted by the Brooks-Dyar Rule. Up through instar IV, the Brooks-Dyar ratio for T. alaskensis ranged 1.30-1.61, but during the IV-V molt head capsule dimensions (sexes pooled) increased by a ratio of 1.09 – comparable to the magnitude of sexual dimorphism in head capsule size within each of the final two larval instars. Individual rearings coupled with 2014-2016 field surveys in nine other ponds suggest that five larval instars is an obligatory trait of this species at this location. As this is the first confirmed case of five larval instars in a chironomid, the phylogenetic uniqueness of this trait needs further investigation.


1968 ◽  
Vol 100 (2) ◽  
pp. 202-206 ◽  
Author(s):  
Louis F. Wilson

AbstractThe willow beaked gall midge, Mayetiola rigidae (Osten Sacken), is univoltine in Michigan. Adults emerge from bud galls on Salix discolor Mühl. and other willows on mornings of warm days in early April. Eggs are laid singly on or near the buds of the host. Head capsule measurements indicate three larval instars. The last two instars each possess a spatula. The first-instar larva emerges in late April and penetrates the soft bud tissues. The gall begins to develop at the beginning of the second instar in mid-May. The third instar appears in early July and continues to enlarge the gall until fall. Prior to overwintering, the larva lines the inner chamber of the gall with silk and constructs one to seven silken septa across the passageway. Pupation occurs in mid-March. The gall deforms the stem and occasionally a galled branch dies or breaks off.


1976 ◽  
Vol 54 (2) ◽  
pp. 266-284 ◽  
Author(s):  
G. Pritchard

Collections of all stages of the crane fly, Tipula sacra have been made over a period of years from a series of abandoned beaver ponds in the Kananaskis Valley, Alberta. The growth of larvae was followed by head-capsule measurements and weights. Eggs hatch within a month; first-instar larvae grow rapidly and enter the second instar after a few weeks. The second instar may last for 3 months and the third instar usually lasts for 6 months, including the first winter. Most larvae spend almost a full year in the fourth instar and overwinter for a second time. However, there was much variation in growth rate within the population. Adult emergence curves were consistent in form in 4 years. Each spanned a period of just over 2 months, although individual adults lived for only a few days. These curves snowed two peaks, the second of which contained 15–20% of the year's emergents. These two groups may represent different cohorts that have grown at different rates, suggesting that the life history may be semivoltine or univoltine. The sex ratio changes from about 1:1 in the third instar to 2:1 in favor of males in the late fourth instar, pupa, and adult.


Zoosymposia ◽  
2011 ◽  
Vol 5 (1) ◽  
pp. 401-407
Author(s):  
SYLVESTER OGBOGU ◽  
WILLIAMS ADU

The life history and density of Cheumatopsyche digitata Mosely (Trichoptera: Hydropsychidae) were examined below Opa Reservoir in Ile-Ife, southwestern Nigeria. This caddisfly is the only species that occurs immediately below the impoundment auxiliary spillway where it closely associates with an aquatic bryophyte, Fontinalis sp. We collected larvae every month between July 2004 and June 2005 as long as larvae were available in the study site. The instar growth ratio was fairly constant and ranged from 1.198 to 1.402 (mean ± standard error = 1.285 ± 0.073) but mean head capsule width increased with larval development. The frequency distribution of head capsule width of larvae clustered into 5 size classes, suggesting 5 larval instars for C. digitata in the study site. Density of larvae ranged from 1,100 to 11,150 inds.m-2 (mean ± SE = 6739  inds.m-2 ± 3904.70), the highest densities occurring in October 2004 during the bloom of Fontinalis. The first larval instar appeared in July 2004. Adult emergence occurred mainly in December 2004 through January 2005 at the onset of reservoir draw-down and death of Fontinalis. These patterns indicate that C. digitata tended to show a univoltine life cycle in the study site.


1968 ◽  
Vol 100 (2) ◽  
pp. 184-189 ◽  
Author(s):  
Louis F. Wilson

AbstractThe taxonomic status of Rhabdophaga sp. cannot be determined until a complete revision of the genus occurs. Rhabdophaga sp. on Salix discolor Mühl. is univoltine in Michigan. Adults emerge in mid-April, and shortly afterward deposit numerous eggs on the setaceous undersurface of emerging willow leaves; larval eclosion occurs between 1 and 2 weeks later. Head capsule measurements reveal three larval instars. The first-instar larva bores into the stem until it reaches the pith. Gall development begins about mid-June shortly after the second instar appears. The third-instar larva overwinters in the gall and the pupa appears in early April. The prolate gall is found on the proximal ends of young willow shoots; heavily galled shoots usually die.


1983 ◽  
Vol 115 (9) ◽  
pp. 1169-1175 ◽  
Author(s):  
J. H. Hainze ◽  
D. M. Benjamin

AbstractThe bionomics of the red pine shoot moth, Dioryctria resinosella Mutuura, a newly described species of shoot borer in red pine, Pinus resinosa Ait., were investigated in Wisconsin sand plains plantations. The appearance of eggs, larvae, pupae, and adults are described. Head-capsule measurements indicated five larval instars. First-instar larvae overwintered in hibernacula. Shoot feeding was generally initiated by third-instar larvae in late May. Cones also were attacked. Pupation occurred in July. The flight period extended from mid-July to mid-September. The sex ratio was 0.53. Only red pine shoots and cones were attacked in a mixed pine stand. Infestation rates were highest along plantation edges, in the top half of the crown and in plantations greater than 20 years of age. Hyssopus rhyacioniae Gahan occurred most frequently among parasitoids reared from larvae and pupae.


1969 ◽  
Vol 101 (3) ◽  
pp. 291-298 ◽  
Author(s):  
Louis F. Wilson

AbstractChrysobothris orono Frost, a buprestid which attacks living red pine (Pinus resinosa Ait.) and jack pine (P. banksiana Lamb.), has a 2-year life cycle and two separate broods in Michigan. Adults emerge from May to July. The eggs are laid singly, usually on the southwest side of a tree; the fifth and sixth whorls from the top are the preferred oviposition sites. Larval eclosion usually occurs in early June. Each larva excavates a cell in the bark and causes the flowing pitch to coagulate into a large pitch mass. The first three instars feed in the bark and the last two instars feed in the xylem. Advanced larvae may reach the fourth instar by fall of the first year; overwintering occurs in the third and fourth instars. The fifth instar, which appears in the spring of the second year, bores a short L-shaped gallery in the xylem and plugs it with frass and wood chips to form a pupal cell. It pupates in the spring of the third year. Adults emerge by chewing through the plug and pitch mass. The bark cell and xylem gallery seldom injure the tree directly, but they remain as defects in the bole after the wounds have healed. Because damage is slight and the insect population low, C. orono is not likely to become an important forest pest.


1956 ◽  
Vol 34 (1) ◽  
pp. 27-36 ◽  
Author(s):  
L. A. Lyons

The seed capacity of red pine cones varies from about 30 to over 110, depending on the size of the cone and its position in the tree crown, and is determined by the number of ovules that are structurally complete at the time of pollination. These ovules occur in a central "productive" region and constitute less than one-half of the total. The remaining ovules, most: of which are in the proximal part of the cone, never become structurally perfect, and do not contribute to seed production. Abortion of ovules in the productive region usually reduces seed production efficiency to 50–60%, and is accompanied mainly by withering of the nucellus in the first year and failure to produce archegonia early in the second year. The extent of ovule abortion during the first year varies indirectly with cone size, seed capacity, and height in tree.


1965 ◽  
Vol 41 (3) ◽  
pp. 290-294 ◽  
Author(s):  
J. D. Gagnon

The fertilizers, Mg at a rate of 100 lbs/acre and K at 200 lbs/acre, were applied around each of 15 red pine (Pinus resinosa Ait.) to promote increased growth in a 20-year-old plantation which had failed to fulfil growth expectations. Successive measurements of diameter and height showed that the fertilizers stimulated diameter significantly after the second growing season, but height only after the third growing season. Beneficial effect of fertilizer applications on diameter and height persisted, and the differences in diameter and height between treated and untreated trees at the end of the seventh growing season was equivalent to two years' current growth.


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