[Cold tolerance of the Pharaoh's ants (Monomorium pharaonis)]. / Zur Kältetoleranz der Pharaoameise (Monomorium pharaonis).

The reaction of Pharaoh's ants to low temperatures was analyzed under laboratory conditions. It was to be clarified in which way low temperature could be used in control measures. In all of the examined ranges of temperature from + 8 degrees C up to --26 degrees C colonies of the Pharaoh's ants were eradicated. The necessary exposition times reached from 30 minutes at --26 degrees C up to nearly 3 weeks at + 8 degrees C. Most favourable for control measures are temperatures near 0 degrees C which lead to the eradication of large colonies within 6 days. The queens were especially susceptable to temperatures below 0 degrees C, whereas temperatures at 10 degrees C are tolerated much better by queens than by workers. In the developmental stages the eggs and the youngest larvae are most resistant, whereas the full grown larvae including sexual larvae die fast. The results demonstrate that using the winterly temperatures in Middle Europe as an integratory method in the control of the Pharaoh's antis of considerable value.

[Mass rearing of the Pharoah's ant Monomorium pharaonis]. / Zur Massenzucht der Pharaoameise Monomorium pharaonis.

New techniques for the mass rearing of the Pharaoh's ant (Monomorium pharaonis) are described. The basic idea in doing this is the enlargement of the surface of the rearing containers in order to guarantee the lapse of normal behaviour such as the search for food and recruitment. The rearing container is an aquarium inside of which a great number of levels of glass are located, which are connected with each other. The watering of the colonies is effected by wet cotton wool in petridishes in the lower parts of the rearing devices. A transposition of the colonies in intervals of 6 to 8 months is recommended. A dispersation method of great colonies to small and physiologically equal laboratory colonies is described. A further mass rearing device allowes a strong enlargement of the surface of normal rearing dishes of 20 to 30 cm in diameter. The basic principle consists in the setting into each other of separate dishes. To prevent an outbreak from these rearing containers the walls are prepared with residues of talcum powder. The methods and devices mentioned make it possible to produce great masses of experimental material under constant control of the developmental status at low costs and little need of space.

[Accessory glands in the reproductive system of the male insect]. / Akzessorische Drüsen im Reproduktionssystem von Insektenmännchen.

Males of insects and ticks influenced the physiology of reproduction of mated females with the secretes of accessory sexual glands (aD) much more than was supposed in the past. The monocoitic behaviour of the females of some species of insects is caused by various secretions (e.g. Matrone in mosquitoes, monogamic factors in the house fly, sexpeptides in Drosophila). Furthermore the preoviposition period is shortened by these secretions whereas the productivity is increased. The food uptake and the autogeny were influenced as well. Besides this other patterns of behaviour changed (e. g. flight activity). Because of their simple structure, the accessory glands are suitable for biochemical investigations. However, in most cases the physiological functions are unknown.--The present knowledge on the functions of the accessory glands is reviewed with special regard to the modes of action of secretions of the accessory glands.

[Genetic control of Blattella germanica]. / Genetische Bekämpfung von Blattella Germanica.

Based on a literature survey, the possibilities of a genetic control of the German cockroach (Blattella germanica) are shown. First, an oversight is given on the cytogenetics of the German cockroach, including some important mutations. Then the control methods by genetic mechanisms are explained. This chapter begins with analysing the relevant biological pecularities. In control measures, the dominant lethal mutations (induced by rays rich with energy and by chemosterilants) have only a chance if they can be applied in the scope of autosterilization of natural populations. Reciprocal translocations may expect maximum consideration in the future of the control of the German cockroach. Some of these are already available in the heterozygote state. But the establishment of homozygous strains was not yet successful up to now. The possibilities of the application of translocation-heterozygotes are discussed. Such mutant strains of cockroaches which bear several translocations in the heterozygous state, offer the most promising way of control. This may even include the population's eradication. A long-lasting regulation of the population may be achieved with the introduction of insects mutated in this manner even in the case if a complete eradication is not attainable. It might be expected that also other genetic mechanisms may contribute, in future, to the improvement of cockroach control. Such mechanisms may be conditional lethal factors, sex distortions, and others more.

[The queen technic for ant control. I. The effect of tepa on laboratory colonies of the pharaoh ant]. / Königinnentechnik zur Ameisenbekämpfung. I. Der Einfluss Von Tepa auf Laborkolnien der Pharaomeise

The present paper discussed at the example of Tepa [Tris (1-aziridinyl) phosphine oxide] in which manner the control of pharaoh's ant in the sense of the "queen technique" with chemosterilants is possible; which points of view must be considered and which condition an acceptable substance should be fulfilled. The application of Tepa is ralized according to various techniques (e.g. dipping, baiting, tarsal contact), in the course of which the baiting technique is preferred. The influence of different concentrations in various baits on the brood, workers and queens are described. In baits with 1% of the substance a permanent sterilization could be achieved. In combination with other population depressing factors (larval and worker mortality) resulted in eradication of the colonies. The action extended also to the larvae of the sexuals, so that the queenless colonies failed in the production of new queens and males. Histological investigations showed in the females at higher concentrations distinct pathological alterations (pycnosis, vacuolizations, proliferation in the follicles epithelium); whereas the spermatogenesis in the males is decreased but not entirely suppressed. At lower concentrations only the fertility but not the fecundity was influenced. A handing-over of recessive lethal mutations to the progeny does not take place. The practical points of view for the use of chemosterilants in the control of pharaoh's ant are discussed. Whereas the low biological stability of Tepa does not exclude an introduction in the practice, the high mutagenic activity prevents an application in the field.

[Evaluation of mirex for the control of pharaoh's ants]. / Zur Bewertung von Mirex bei der Pharaoameisenbekämpfung

The paper analyses the mode of action of the organic chlorine compound Mirex in laboratory colonies of the pharaoh's ant Monomorium pharaonis under the special view of practical use in control measures in comparison with the related insecticide Chlordecone (Kepone). Similar to Chlordecone the queens are very susceptible towards the action of Mirex. According to the regression lines of the mortality the best concentrations for practical control measures are in the range of 0.1 to 1%, respectively. Under laboratory conditions a reliable eradication is effected by an application of 0.001% Mirex over a period of three weeks. Such a treatment lead to the loss of reproductive capacity of the remaining living queens. These queens do not recover after transmission to normal colonies. The larvae were influenced in the same manner as the adults. At the recommended level of Mirex all of the larvae disappear within the first five days of application of the poison bait. Also a short termed use lead to a long lasting damage of the ant societies. Between different baits no significant difference could be demonstrated even when one bait obviously was better accepted than another. Because of the strong effect on intact colonies Mirex should be recommended for the control of this ant pest.

[Development of resistance in Pharaoh's ant (Monomorium pharaonis)]. / Resistenzentwicklung bei der Pharaoameise (Monomorium pharaonis)

The possibility of resistance development in the pharaoh's ant Monomorium pharaonis in regard to insecticides and chemosterilants in general and in the special case of sodium arsenate is discussed. The low number of sexuals and the long duration of generations reduced the possibility of the development of resistance in social insects to a great extent. Although the pharaoh's ant offers relatively good possibilities for the selection of resistance on account of the polygyny, the duration of generations in the range of a whole year under field conditions and the isogeny of the colonies diminished the development of resistance. Experimental investigations for the selection of resistance to sodium arsenate in laboratory colonies with artificially shortened sequence of generations are presented. Following six generations, no enlargement of tolerance or true resistance but a clear sensitivity could be stated. This sensitivity leads to an eradication of the colonies. It is pointed out, that in pharaoh's ant a development of resistance against the lethal action of sodium arsenate and carbaryl is impossible, because of the protection mechanism of the social food chain.

[The effect of chlordecone (Kepone) on the laboratory colonies of the Pharaoh's ant Monomorium pharanois]. / Die Wirkung von Chlordecone (Kepone) auf Laborkolonien der Pharaoameise Monomorium pharaonis

The control of the Pharaoh's ant Monomorium pharaonis is very difficult because of the social way of life in this insect pest. In regard to the reported good suppressing results of Chlordecone we analyzed the mode of action in this compound at laboratory colonies of the pharaoh's ant. Commercial gel and granular formulations as well as selfmade baits have been tested. The best results showed the granular bait on the basis of ground nut butter, while the effects of all of the others was much weaker. The pure gel, developed for cockroach control, was like the application in drinking water without success. The treatment of the colonies after a starvation period of 60 hours improved all of the effects. Sterility (fertility, fecundity) in the surviving queens was not measurable. For practical control measures the often recommended prebaiting is not at all desirable. The action on the worker ants is good, but the special mode of action based on the selective mortality in the queens and its detailed effects are unknown. Through the early absence of queens in the colonies will be induced in many cases a production of new sexuals, which compensate the success of the poison and allow the colonies to recover. The treatment leads faster to an eradiction if the ET90 to workers mortality reached earlier than that in the queens. Successful control of pharaoh's ant will Chlordecone should be considered with reserve. Nethertheless Chlordecone is in the present situation of pharaoh's ant control one of the best so far known organic-synthetically insecticides.