Multiplexing is far more effective through microarrays, which is an ordered array of hundreds of molecular probes specific for different target RNAs bound to a solid support, usually a slide. Most microarray technology has been developed for nucleic acid probes, although protein-based arrays are also being developed (Sage, 2004). The hybridization of RNA target sequences to these probes to these probes can be detected by a variety of methods (de Miranda, 2008), including PCR and sequencing. Numerous honey bee microarrays have been designed, including honey bee immune gene-pathogen arrays (Evans, 2006; Runckel et al., 2011) and a honey bee virus array (Glover et al., 2011). Microarrays are being superseded for research purposes by high-throughput sequencing technologies, but retain a future in routine screening applications, due to their adaptability and high multiplexing capacity (Glover et al., 2011). See also the microarray section in the BEEBOOK paper on molecular methods (Evans et al., 2013).