Reproduction

     Aphodius prodromus beetles reproduce sexually.  They have the typical life cycle of a beetle which involves laying eggs in which develop to become larvae, pupae, and then an adult. Below is a simple diagram of the life cycle of beetles (Animal Corner 2003-2013).

 

 
Interestingly enough, A. prodromus beetles do not actually lay their eggs in dung pats.    Instead they lay their eggs in the soil near dung piles (Gittings and Giller 1997).  The larvae then develop there on the roots of plants and decomposing plant matter (Gittings and Giller 1997).  It is unsure what exactly the larvae food source is.  It is most likely a combination of both dung, brought to where the larvae are developing, and decomposing plant matter that they use(Sladecek et al. 2013).  This type of dung beetle can be considered a relocator, meaning their larvae do not reach the dung pat at any point in their development (Sladecek et al. 2013).  Relocating adults do one of two things to create a nest for their eggs (Arnaudin 2012; Sladecek et al. 2013).  One type of relocating is called tunneling.  Tunnelers are beetles that burrow down into the soil forming nesting chambers directly underneath, or nearby, the dung source.  These beetles use dung and make balls out of it to use as the food source for the larvae.  The other method is called rolling.  The beetles also make balls out of dung, but they differ from tunnelers because they roll the balls away from the dung pile and shallowly bury it in the soil.  They then will lay a single egg on top of it. (Arnaudin 2012).    
   

A. prodromus female beetles have an accumulated sequential type of ovarian development.  Females may have up to twenty-three mature eggs in their ovaries.  First, eggs develop in separate ovarioles until there is a mature egg in the individual ovarioles.  At that point, the second egg starts to develop sequentially in the ovarioles, while the mature eggs accumulate in the females two ovaries. (Gittings and Giller 1997). Once all the eggs are mature, the female leaves the dung pile and goes to lay her eggs in the soil.  After fertilization, the eggs then go through the process of being larvae, to pupae, and then eventually an adult.

The general life cycle of a beetles is as follows:                                                                                                      
                                                                                                                                                                                                                            Beetles undergo complete metamorphism.  They start as an egg, hatching about four to nineteen days after fertilization.  The larval stage marks a period of tremendous growth.  The beetles molt their exoskeleton many times and grow in size and elongates.  After growth they enter the pupal stage, which is a period of transforming into an adult (Animal Corner 2003-2013).  For A. prodromus, this pupal stage takes place over the winter months.  As an adult, A. prodromus beetles have what is considered to be an early successional occurrence, meaning their adult flight period occurs in the spring, and then again in autumn (Gittings and Giller 1997).  Adult flight period is defined as being the period of adulthood, meaning they have wings (Yoshida and Katakura 1986).  In A. prodromus beetles, the time in between their spring and autumn adult flight periods is marked by an inactive period (Gittings and Giller 1997). In the autumn season, A. prodromus adults feed on the dung before hibernation during the wintering months.  The occurrence of A. prodromus beetles in early spring is most likely a result of the beetles coming out of hibernation from the winter months (Holter 1982).

 

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