Parasitism of the deer ked,Lipoptena cervi,on the moose,Alces alces,in eastern Finland

The deer ked, Lipoptena cervi L. (Diptera: Hippoboscidae), is an ectoparasitic fly that spread to Finland in the early 1960s from the southeast across the Soviet border. It is currently a common parasite of the moose, Alces alces (Artiodactyla: Cervidae), in the southern part of the country and its area of distribution is gradually spreading to Finnish Lapland, where it will come into contact with another potential cervid host, the semi‐domesticated reindeer, Rangifer tarandus tarandus. The aim of this study was to determine the intensity of deer ked parasitism on the moose in eastern Finland. Whole skins of 23 moose were examined for the presence of deer keds, which were extracted and their total numbers estimated. The intensity of deer ked parasitism was correlated to the age, sex, skin area and anatomical region of the host. Bulls had the highest total number of keds (10616 ± 1375) and the highest deer ked density (35.7 ± 4.4 keds/dm² of skin). Cows had a higher total number of keds than calves (3549 ± 587 vs. 1730 ± 191), but ked densities on cows and calves were roughly equal (11.8 ± 1.7 vs. 9.4 ± 1.1 keds/dm² of skin). The density of keds was highest on the anterior back, followed by the posterior back, front limbs, abdomen, head and hind limbs. The sex ratio of deer keds was close to equal (male : female, 1.0 : 1.1). After they had consumed blood, male keds were heavier than females. As the total numbers and densities of deer keds were higher than reported previously on moose or for any other louse fly species, the effects of parasitism on the health of the host species should be determined.     

Effect of Abscisic Acid and Other Plant Hormones on Growth of Apical and Lateral Buds of Seedlings

The effect of abscisic acid (AbA) on the growth of lateral and apical buds was studied in seedlings of Pisum sativum and some other species. The hormone was applied in three different ways: 1) directly to the lateral bud on the second node of decapitated pea seedlings as 5 μI droplets in an ethanolic solution; 2) to the cut surface of decapitated seedlings: 3) to the apical bud of intact plants. AbA directly applied in amounts of 5 to 0.1 μg to the lateral bud of the second node of decapitated seedlings had a strong inhibitory effect on the bud. Application to the cut surface of seedlings decapitated about 5 mm above the second node resulted in slight inhibition of the lateral bud on the second node and in growth promotion of the bud on the first node. When AbA at 10 to 0.1 μg was applied to the apical bud of intact seedlings, the growth of this bud was inhibited but the lateral buds grew out. It is concluded that the release of the lateral buds from apícal dominance is the result of the inhibitory effect of AbA on growth of the apical bud and of low transport of AbA. This conclusion is supported by application of GA₃ and IAA, individually and each combined with AbA.     

Transport of Abscisic Acid-2-C-14 in Intact Pea Seedlings

When abscisic acid-2-C-14 (AbA-2-C-14), 1 μg in 5 μl 40% ethanol, is applied to the apical bud of light-grown pea seedlings, C-14 is translocated downwards only in very small amounts and does not enter the root. In contrast to this, C-14 from indoleacetic acid-C-14 (IAA-2-C-14) applied in the same manner is translocated to the root where it accumulates. When AbA-2-C-14 is injected to the stem tissue at the apical bud, more labelled material is transported downwards than after application to the surface. Application of AbA-2-C-14 to an expanded leaf results in considerable accumulation of C-14 in the growing apical parts and in the lateral roots.     

Seasonal Onset and Disappearance of Diurnal Rhythmicity in Melatonin Secretion in Female Reindeer

The reindeer (Rangifer tarandus tarandus) is a semidomesticatedholarctic ruminant subject to economic activity. Our researchwas carried out in Northern Finland, at latitude 69°10'N,where the daily light-dark rhythm has a polar pattern: constantdarkness starts on November 26th and lasts about 10 weeks, whilethe polar day of about 10 weeks starts on May 15th. We had previouslyfound distinct daily rhythms in reindeer melatonin secretionin autumn, winter and spring but not at all in summer. Herewe determine how the daily melatonin pattern develops afterthe period of polar day and how it disappears at the beginningof that period. Melatonin showed increased concentrations verysoon after the first sunset. Thereafter the daily pattern developedgradually and was fully developed around the autumn equinox.Its shape was asymmetric and the maximum amplitude occurrednear the end of the dark period. The disappearance of this dailypattern in spring was also gradual. The maximal concentrationsdepended on ambient illumination, especially the duration ofthe dark period. In spring the reindeer appeared to be moresensitive to light than in autumn. Additionally illuminationof the same magnitude suppressed serum melatonin levels moreeffectively before midnight than afterwards, which is in accordancewith the asymmetric secretion pattern. Melatonin secretion wasalways suppressed when the ambient illumination exceeded 1,0001x. The pattern of melatonin secretion in reindeer is differentfrom those described earlier and hence the reindeer may serveas a model for melatonin secretion at high latitudes. We suggestthat, in addition to the duration of the melatonin secretion,changes in amplitude are also of importance in the reindeer.     

Salt licks do not increase local densities of the deer ked,Lipoptena cervi,an abundant ectoparasite of cervids

The deer ked, Lipoptena cervi (Diptera: Hippoboscidae), is a common ectoparasite of the moose, Alces alces (Artiodactyla: Cervidae). Salt licks are widely used to manipulate moose movements to prevent damage to saplings and traffic accidents. They may cause moose to gather in small areas, which could create aggregates of deer ked pupae as the parasite is a short‐distance flyer and its dispersion depends on its hosts. We investigated whether the population density of flying deer keds could be influenced by manipulating salt licks and how environmental variables affect parasite density. Densities were estimated in 40 experimental sites with four treatments (no salt licks, introduced salt licks, removed salt licks, permanent salt licks) in September during 2007–2010. Forest edges, mixed forests on mineral soil and coniferous forests on peat soil were the habitats with high numbers of parasites. The manipulation of salt licks seemed to be ineffective in reducing the density of deer keds as the only factor to show statistical significance with parasite numbers in the mixed‐model analysis was year of determination. Annual deer ked densities correlated with the abundance of moose in the region. Moreover, high spring and summer temperatures seemed to increase the numbers of flying imagos.