134 



BR. J. ENT. NAT. HIST., 6: 1993 



Table 4. Summary of the responses of ants on encountering ladybirds (carnivorous and non- 

 carnivorous species combined). 



Ant response 



Investigated, then escalated 

 Investigated only 



Before 









ladybird 



While 



0-2 mins after 



>2 mins after 



reaches 



ladybird is 



ladybird has 



ladybird has 



colony 



on colony 



left colony 



left colony 



11 



33 



18 



15 



18 



8 



6 



15 



level of response and the level more than 2 minutes after the ladybirds have left the 

 colony (x? = 0.87, P>0.1). Notably, there is also no significant difference between 

 the level of ant response to ladybirds on the colony and in the first 2 minutes after 

 the ladybirds have left the colony (xf = 0.27, P>0.1). We conclude that there is a 

 significant increase in ant hostility when the ladybird reaches the colony. This level 

 of hostility begins to decrease some time after the ladybird leaves the colony and has 

 effectively returned to the base level after about two minutes. 



Species-specific notes 



The above summary of results applies to most of the ladybird species used, 

 but A. bipunctata and C. 7 -punctata in particular. Although we did not do enough 

 repeats to analyse the data statistically for differences between species, notes on 

 the behavioural interactions of each species were made. Here follows a summary of 

 these notes. 



Propylea 14-punctata (14-spot ladybird) 



On contact with ants, it employs a strange jolting action which appeared to be an 

 attempt to shake ants from its back. 



Myrrha 18-guttata L. (18-spot ladybird) 



The ants seemed very aggresive towards this species and attacked continuously 

 both before it reached the colony and afterwards on leaves at some distance from 

 the colony. The ladybird continually ran away but the ants persisted in their attacks. 

 It has been suggested that this species is a Scots pine specialist, breeding almost 

 exlusively in the higher branches of mature trees (Majerus, 1988; Majerus & Kearns, 

 1989). It is feasible that by restricting reproductive activity, and in particular 

 oviposition, to the tops of these tall trees, they avoid the extremely violent behaviour 

 of the ants towards them. Why ants should react more aggressively to this species 

 than others is not known. 



Anatis ocellata L. (eyed ladybird) 



When an ant managed to get hold of its leg the ladybird successfully dislodged 

 the ant by kicking with its other legs. A larva of this species was the only ladybird 

 which the ants successfully killed and carried off. Up to seven ants at a time carried 

 the dead larva. The ants would lose interest for several minutes at a time and then 

 start again, always moving the body down the plant. 



