Flower Associations of Mimetic Syrphidae (Diptera) in Northern Michigan

Collections of specialized (high fidelity) mimetic Syrphidae in northern Michigan revealed 19 species associated with 18 flowering plants. Almost 97% of these syrphids were taken on seven plant species or species groups, all with conspicuous white or yellow blossoms, and all but one with aggregate inflorescences. Pastinaca sativa (Umbelliferae) is visited by many mimetic syrphids in northern Michigan but by very few in central Illinois; the opposite is true of Sambucus canadensis (Caprifoliaceae). In northern Michigan mimetic syrphids exploit a sequence of blossoming plants that more or less replace each other as the season progresses. The cooling effect of Lake Michigan slows the development of vegetation and the appearance of mimetic. syrphids along the shore by over two weeks as compared to a transect only 6.5 to 17 km inland. Because of the normally cooler temperatures in northern Michigan, syrphids appear on flowers later in the day and remain there longer than they do in central Illinois

Adult Emergence in Two Univoltine \u3ci\u3eCallosamia Promethea\u3c/i\u3e Populations: Preponderance of the Early Emerging Morph in the North and of the Late Emerging Morph in the South (Lepidoptera: Saturniidae)

Callosamia promethea is common on wild black cherry, Prunus serafina, at the University of Michigan Biological Station in northern lower Michigan. In this area the early emerging morph is preponderant, while to the south in northern Indiana, the late emerging morph is preponderant

Diapause and Emergence Patterns in Univoltine and Bivol Tine Populations of Promethea (Lepidoptera: Saturniidae)

Data are presented on the diapause and the seasonal emergence patterns of the adults of a univoltine Callosamia promethea population from northern Indiana and a partially bivoltine population from central Illinois. At Urbana, Illinois, the median emergence date of adults from overwintering Illinois pupae was about a month earlier than that of adults from overwintering Indiana pupae. Illinois samples had a much longer emergence period than Indiana samples. Indiana samples showed a slight tendency toward a bimodal emergence pattern, a few individuals emerging in late May and the rest emerging as a tightly synchronized group from late June to mid-July. Early emerging lIIinois moths produced mostly non.diapausing progeny, but the proportion of diapausing progeny increased as the season progressed. Some females produced both diapausing and non· diapausing progeny. Adults from non-diapausing pupae from early August to early September

Flowers Associations and Mating Behavior or its Absence at Blossoms by \u3ci\u3eSpilomyia\u3c/i\u3e Spp. (Diptera, Syrphidae)

(excerpt) Syrphid flies of many species visit blossoms to obtain nectar and pollen (see Waldbauer 1983 for referencesl. Many of these syrphids, in common with other insects (Parker 1978), also find mates at the blossoms. Males of these syrphid species make aerial patrols of inflorescences frequented by females, alternating these patrols with sitting on foliage. l11ey pounce on or chase insects of various species and swiftly initiate copulation with can specific females (Collet and Land 1975; Maier 1978; Maier and Waldbauer 1 979a,b)

Ibsen and Shaw: A Comparison

It is the intention of this paper to demonstrate that, above and beyond such purely historical evidence, Shaw and Ibsen cannot and should not be classified together, or even seen as particularly similar apart from the fact that they dealt with some of the same themes, because they had in fact two completely different world-views. This difference in viewpoint also accounts in large measure for Shaw\u27s distortion, and in some cases downright misunderstanding, of Ibsen

An Improved Procedure for Laboratory Rearing of the Corn Earworm, \u3ci\u3eHeliothis Zea\u3c/i\u3e (Lepidoptera: Noctuidae)

An improved method for the laboratory rearing of the corn earworm. Heliothis zea, described. The rearing medium is a modification of the commonly used wheat germ An oviposition chamber, a feeder for adults, and a simple and inexpensive contrnlled humidity chamber are described

Longevity and Weight Loss of Free-flying Male Cecropia Moths, \u3ci\u3eHyalophora Cecropia\u3c/i\u3e (Lepidoptera: Saturniidae)

During their spring flight season, free-ranging male cecropia moths lived a maximum of 12 days (one of 124 recaptured moths of 387 released moths). The number of survivors declined precipitiously after day five; five to seven days is probably the usual life span. The recaptured moths did not have different initial weights than those that were not recaptured. The larger the moth the more absolute weight it lost and the faster it lost weight during the first few days. A moth lost about 20% of its weight during the first night of flight and accumulated about a 40% weight loss during the remainder of its life

Protein intake by gypsy moth larvae on homogeneous and heterogeneous diets

Food selection behaviour, food utilization efficiency and growth performance of a generalist insect, the gypsy moth ( Lymantria dispar (L.), Lepidoptera: Lymantriidae), were examined with respect to variation in food nitrogen concentration. The results suggest that gypsy moth do not suffer physiologically and in fact may benefit from intraplant variation by selective feeding. When provided with diet cubes containing identical nitrogen concentrations, control larvae tended to consume food from a single cube. This behaviour contrasted with that of larvae provided cubes differing in nitrogen concentration. These larvae tended to consume more from the high nitrogen cube, but allocated feeding more evenly among diet cubes than did control larvae. Overall, larvae mixed foods so as to obtain a mean concentration of 2.9-3.2% nitrogen, a concentration assumed to approximate the ’intake target’. Larvae confined to single nitrogen concentrations mitigated the impact of imbalanced diets on body composition via both pre-ingestive and post-ingestive compensation. When confined to a specific nitrogen concentration, larvae adjusted their intake to the point of best compromise. In this case, this was the geometrically closest point to the estimated intake target. Larvae with a choice of foods that deviated more than ±1% from each other in nitrogen concentration grew as well as or better than larvae without a choice but given identical mean nitrogen concentrations. These results demonstrate that selectivity and nitrogen consumption by gypsy moth larvae are altered according to the particular choices available. Insects may benefit from intraplant variation in food quality because such variation provides the opportunity to choose foods and mix them in ways that permit close matching with the intake target. Variation may be particularly important to insects which must offset changing nutritional demands.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73505/1/j.1365-3032.1993.tb00615.x.pd

A Photoelectric Colorimeter: Its Application in the Measurement of the Concentration of Colored Substances in Solution

The concentration of plant substances such as the chlorophylls and carotenes can most readily be quantitatively measured by colorimetric methods. Colorimetry also offers a rapid method for the quantitative determination of organic substances such as sugars, oxidases, and inorganic ions as magnesium, iron and phosphates, in which colors can be developed when in combination with certain other ions in solution. The personal equation in such measurements has long been known to contribute a source of error where such methods have been used. An extended bibliography of which part 2 of this paper is composed, has several references which show that the use of photoelectric cells in this regard improves the accuracy of colorimetric investigations. A simple photoelectric colorimeter is here described and experimental data presented in support of certain specifications of construction and operation

A Quantitative Spectrographic Study on the Effects of the Alkali Metals upon the Determination of Calcium

It has been known for some time that in spectrographic analysis each element present has some effect upon the other elements present. Our investigation of the effect of the alkali metals on calcium showed that, in general, the intensity of the spectral lines of calcium increased with an increase in the percentage of the alkali metal present. However, there is a decrease in the intensifying effect at the higher concentrations. The chlorides of the alkali metals used were in concentrations varying from 1.0 per cent to 0.031 per cent, and the concentrations of the calcium solutions used varied approximately over the same range. Slides were used to show the apparatus used (including the wedge sector), typical spectrograms, and also to show some of the data obtained in graphical form